When it comes to describing situations, feelings, or behaviors that are difficult to comprehend, idioms often come to our rescue. They help us express complex emotions in a way that’s both creative and colorful.
Among the various categories of idioms, those for describing something “crazy” are particularly interesting. Whether you’re trying to explain a wild situation or an unpredictable person, idioms give your words an extra flair that straight talk just can’t match.
In this article, we’ll explore 20 idioms for crazy that will add a touch of fun and depth to your conversations. From everyday expressions to quirky phrases, these idioms will help you describe madness, confusion, and eccentricity in a way that’s both thoughtful and engaging.
So, let’s dive into these fun expressions and get ready to enrich your vocabulary!
What is an Idiom for Crazy?
An idiom for crazy refers to a set phrase or expression that describes something that is considered wild, absurd, or unconventional.
These idioms often help us express complex emotions, situations, or behaviors in a more creative and engaging manner. The beauty of using idioms for describing craziness lies in how they bring humor and vivid imagery to conversations.
The phrases are often figurative, meaning that their meanings aren’t taken literally but convey a deeper, often exaggerated, sense of the situation.
List of Idioms for Crazy
1. Barking Mad
2. Off One’s Rocker
3. Out of One’s Mind
4. A Few Sandwiches Short of a Picnic
5. Batty
6. As Mad as a Hatter
7. One Flew Over the Cuckoo’s Nest
8. Nuts
9. Loony Tunes
10. Not Playing with a Full Deck
11. Bonkers
12. Crazy as a Loon
13. Lost Their Marbles
14. Off the Wall
15. Screwy
16. Mad as a March Hare
17. In a Tizzy
18. Completely Unhinged
19. Off the Deep End
20. Wacko
1. Barking Mad
“Barking mad” is a fun and vibrant expression used to describe someone who is acting irrationally or is completely out of their mind.
Definition: This idiom suggests that someone is behaving in a crazy, unpredictable, or irrational manner, as if they were a barking dog.
In a sentence: “You want to quit your job and move to the mountains? That’s barking mad!”
Example: A person decides to sell all their belongings and live in the jungle with no supplies. Others would say they are barking mad.
Explanation: This phrase paints a picture of a person losing control, as if they were barking wildly, much like an out-of-control dog.
Other ways to say:
- Completely Reckless
- Out of their mind
- Off the wall
- Out of control
- Losing it
2. Off One’s Rocker
If someone is described as being “off their rocker,” it means they’re behaving in a crazy or irrational way.
Definition: This idiom comes from the idea of someone literally falling off a rocking chair, symbolizing a loss of balance or mental control.
In a sentence: “I think she’s off her rocker if she believes in that conspiracy theory.”
Example: A person spends all their savings on lottery tickets, believing they are guaranteed to win. Others might say they are off their rocker.
Explanation: The phrase evokes the image of someone being unsteady, out of their usual state, and acting erratically.
Other ways to say:
- Losing their mind
- Totally unhinged
- Out of it
- Off their game
- Unstable
3. Out of One’s Mind
“Out of one’s mind” is a popular idiom that describes someone who is mentally disturbed or behaving in an unusual or crazy manner.
Definition: This idiom suggests that the person has lost touch with reality, as if their mind has gone outside of itself.
In a sentence: “He must be out of his mind to think that would work.”
Example: A person attempts to drive across a frozen lake despite warnings. Others would say they are out of their mind.
Explanation: It refers to someone acting as if they have lost their usual rational thinking, often behaving erratically or in a surprising manner.
Other ways to say:
- Reckless
- Crazy as a loon
- In a daze
- Mad as a hatter
- Not thinking straight
4. A Few Sandwiches Short of a Picnic
This idiom is a playful way to describe someone who is not quite mentally sound, as if they’re missing something important in their thinking.
Definition: The phrase suggests that someone is lacking the necessary mental faculties, much like a picnic would be incomplete without enough sandwiches.
In a sentence: “He tried to build a house out of cardboard—he’s definitely a few sandwiches short of a picnic.”
Example: A person believes they can run a marathon without any training and minimal food. Others might say they are a few sandwiches short of a picnic.
Explanation: The idiom uses the metaphor of a picnic missing essential items to describe someone who is acting foolishly or irrationally.
Other ways to say:
- Not all there
- Not the sharpest tool in the shed
- A couple of bricks short of a load
- Lacking a few screws
- Off their rocker
5. Batty
“Batty” is a quirky, lighthearted idiom that refers to someone acting eccentric or crazy.
Definition: The word comes from the idea that bats are erratic and unpredictable in flight, reflecting someone who is acting in a similarly disordered or odd way.
In a sentence: “That guy’s completely batty if he thinks that idea will work.”
Example: A person talks to their plants as if they were having a full conversation. Others might say they are batty.
Explanation: The term is often used in a less harsh way, signaling someone is being whimsical or goofy rather than truly disturbed.
Other ways to say:
- Silly
- Loony
- Wacky
- Quirky
- Eccentric
6. As Mad as a Hatter
This idiom finds its roots in the 19th-century perception of hat makers, who were thought to suffer from madness due to mercury exposure.
Definition: It means someone who is completely crazy, often in a wild or whimsical way, resembling the unpredictable nature of a mad hatter.
In a sentence: “Did you hear his plans for the weekend? He’s as mad as a hatter!”
Example: A person suddenly decides to dress up in a superhero costume and patrol the neighborhood at night. Others might say they are as mad as a hatter.
Explanation: This expression is often used for people with strange ideas or behaviors that appear irrational or illogical but still amusing.
Other ways to say:
- Totally bonkers
- Out of their mind
- Crazy as a loon
- A few bricks short
- Unbalanced
7. One Flew Over the Cuckoo’s Nest
This idiom is inspired by the famous novel and movie, symbolizing a person who is mentally unstable or acting completely irrationally.
Definition: It refers to someone who has lost their sanity or is behaving in a way that suggests they belong in a mental institution.
In a sentence: “After quitting his job to chase UFOs, it’s like he’s one flew over the cuckoo’s nest.”
Example: A person suddenly sells all their belongings and moves to a deserted island because they believe the world is ending. Others might say they have one flew over the cuckoo’s nest.
Explanation: This phrase is often used humorously or seriously to describe people who act in ways that make them seem detached from reality.
Other ways to say:
- Lost their mind
- To go out of control
- Not in their right mind
- Needs help
- Out of touch with reality
8. Nuts
“Nuts” is a simple and commonly used idiom for describing someone who is acting crazy, silly, or overly enthusiastic.
Definition: It means someone is behaving irrationally, unpredictably, or in an extreme manner.
In a sentence: “You’re nuts if you think you can run a marathon without training!”
Example: A person spends their entire salary on lottery tickets believing they will win. Others might say they are nuts.
Explanation: This word is often used in an informal and playful way, sometimes to express disbelief or astonishment.
Other ways to say:
- Crazy
- Bonkers
- Reckless
- Out of their mind
- Unhinged
9. Loony Tunes
“Loony tunes” is a humorous way to describe someone who is acting silly, foolish, or outright crazy.
Definition: It suggests someone is behaving in an exaggeratedly eccentric or irrational way, similar to cartoon characters.
In a sentence: “Ever since he started believing he’s a secret agent, he’s been acting loony tunes.”
Example: A person starts dressing like a superhero and patrolling the streets at night. Others might say they are loony tunes.
Explanation: This phrase comes from the classic animated series, emphasizing exaggerated, wacky behavior.
Other ways to say:
- Wacky
- Goofy
- Off the deep end
- Totally nuts
- Out there
10. Not Playing with a Full Deck
This idiom is often used to describe someone who is lacking common sense or not thinking logically.
Definition: It implies that a person is missing some mental sharpness, just like a deck of cards that is incomplete.
In a sentence: “Anyone who willingly walks into a lion’s cage must not be playing with a full deck.”
Example: A person decides to drive blindfolded as a “fun challenge.” Others might say they are not playing with a full deck.
Explanation: This phrase humorously suggests that someone is making irrational choices, as if they are mentally incomplete.
Other ways to say:
- Not all there
- A few cards short
- Not the brightest bulb
- A couple of screws loose
- Missing a few marbles
11. Bonkers
“Bonkers” is a fun and expressive way to say someone is acting in a wildly irrational or excited manner.
Definition: It means completely crazy or behaving in a way that defies logic.
In a sentence: “He’s completely bonkers to think he can climb Everest without any training!”
Example: A person adopts 50 cats overnight without a plan to care for them. Others might say they are bonkers.
Explanation: This word is often used in a playful way to describe extreme behavior.
Other ways to say:
- Reckless
- Wacky
- Off the wall
- Out of their mind
- Losing it
12. Crazy as a Loon
This idiom compares a person’s behavior to a loon, a bird that makes eerie sounds and seems unpredictable.
Definition: It describes someone who is acting wildly eccentric or irrational.
In a sentence: “He keeps talking to his plants as if they’re answering—he’s crazy as a loon!”
Example: A person starts yelling at their own shadow, believing it’s following them. Others might say they are crazy as a loon.
Explanation: This phrase suggests that the person’s actions are completely bizarre and unpredictable.
Other ways to say:
- Out of their mind
- Not all there
- Off their rocker
- Totally nuts
- Unhinged
13. Lost Their Marbles
“Lost their marbles” is a lighthearted way to say someone has lost their sanity or is acting strangely.
Definition: It means that a person has become confused, irrational, or mentally unstable.
In a sentence: “If he thinks he can finish a 500-page book in one night, he must have lost his marbles.”
Example: A person starts wearing a winter coat in the middle of summer and insists it’s freezing. Others might say they have lost their marbles.
Explanation: The phrase comes from the idea of someone misplacing their mental faculties, much like losing actual marbles.
Other ways to say:
- To go out of control
- Out of their mind
- Not thinking straight
- Totally bonkers
- Unstable
14. Off the Wall
“Off the wall” describes something or someone that is eccentric, unexpected, or downright crazy.
Definition: This idiom implies that a person’s behavior is so out of the ordinary that it’s almost as if it came from an unexpected, wild place.
In a sentence: “Her idea to start a business selling pet rocks is completely off the wall!”
Example: A person begins to wear pajamas to work every day as part of a “revolutionary fashion trend.” Others might say they are off the wall.
Explanation: It suggests behavior that is unconventional or shocking, not following the usual pattern.
Other ways to say:
- Eccentric
- Unusual
- Wild
- Bizarre
- Wacky
15. Screwy
“Screwy” is a casual, informal term to describe someone who is acting in an unusual or crazy manner.
Definition: It implies that something is out of order or not functioning properly, often used to describe irrational or unpredictable behavior.
In a sentence: “He’s acting a bit screwy these days, like he’s living in another world.”
Example: A person decides to quit their stable job to travel the world with no plans. Others might say they are screwy.
Explanation: This term is typically used in a more lighthearted or humorous context, reflecting actions or ideas that appear illogical.
Other ways to say:
- Nutty
- Out of control
- Unpredictable
- Kooky
- Bonkers
16. Mad as a March Hare
“Mad as a March hare” comes from the behavior of hares in the spring, known for their erratic and seemingly reckless actions.
Definition: It means someone is acting irrationally or wildly, often in a funny or exaggerated way.
In a sentence: “He’s mad as a March hare if he thinks he can juggle work, school, and a full social life.”
Example: A person begins to run in circles, shouting nonsense, because they believe they’re training for a race. Others might say they are mad as a March hare.
Explanation: The phrase refers to the erratic and wild behavior of hares during the breeding season, symbolizing someone who is acting in an unpredictable and crazy manner.
Other ways to say:
- Wild
- Unhinged
- Crazy as a loon
- Frenzied
- Eccentric
17. In a Tizzy
“In a tizzy” describes a state of confusion or agitation, where someone is behaving in a frantic or overly emotional way.
Definition: It suggests that a person is caught up in a chaotic or anxious state, often resulting in irrational actions.
In a sentence: “She was in a tizzy over the smallest mistake in her presentation, as if the world was ending.”
Example: A person starts running around frantically looking for their keys even though they are in their pocket. Others might say they’re in a tizzy.
Explanation: The phrase conveys a state of mental disarray or high stress, leading to exaggerated, frantic behavior.
Other ways to say:
- Flustered
- Agitated
- Frazzled
- Frantic
- Out of sorts
18. Completely Unhinged
“Completely unhinged” refers to someone who is acting in a wildly unpredictable or irrational manner.
Definition: It means a person has lost control of their emotions, logic, or behavior to the point of madness.
In a sentence: “Ever since the meeting, he’s been completely unhinged, shouting at anyone who disagrees with him.”
Example: A person starts yelling at their computer because it freezes, despite it being a minor issue. Others might say they are completely unhinged.
Explanation: This phrase suggests that someone is behaving without restraint, often in an emotional or irrational way.
Other ways to say:
- Out of control
- Unstable
- Wild
- Erratic
- Over the top
19. Off the Deep End
“Off the deep end” refers to someone who has gone beyond the point of reason or control, behaving in a way that is dangerously irrational.
Definition: This idiom is used when someone starts acting in an extreme or reckless way, as though they’ve lost all sense of logic.
In a sentence: “After losing his job, he went off the deep end, quitting everything in his life, including his hobbies and relationships.”
Example: A person suddenly decides to quit their job, sell their house, and move to a remote island with no plan. Others might say they’ve gone off the deep end.
Explanation: The phrase uses the metaphor of diving into deep waters, suggesting someone has taken things too far into an irrational state.
Other ways to say:
- Lost control
- Gone mad
- Lost their bearings
- Over the edge
- Out of their mind
20. Wacko
“Wacko” is an informal term used to describe someone who is acting extremely crazy, silly, or unpredictable.
Definition: It refers to behavior or ideas that are wildly irrational or strange, often used humorously.
In a sentence: “She came up with the wacko idea of starting a business that only sells socks for dogs.”
Example: A person starts collecting thousands of rubber bands for no apparent reason. Others might say they are wacko.
Explanation: This term is often used in a playful or casual way to describe someone who is acting in a wild, funny, or unexpected way.
Other ways to say:
- Nutty
- Crazy
- Loony
- Offbeat
- Outlandish
Other Ways to Say Idioms for Crazy
- Expressions for Madness
- Phrases for Insanity
- Sayings for Eccentricity
- Figurative Speech for Being Unstable
- Colloquial Terms for Craziness
Final Thoughts
Idioms are a fantastic way to spice up our language and express thoughts in unique and creative ways. When it comes to describing someone or something as crazy, idioms like “off the wall”, “nuts”, or “bonkers” add humor, color, and personality to conversations.
These expressions help us capture the essence of eccentric or irrational behavior, making them a fun and useful addition to your vocabulary. So next time you encounter something wild or outrageous, don’t just call it crazy—use one of these idioms to keep your speech lively and engaging!
FAQs
1. What is the origin of “mad as a March hare”?
This idiom comes from the erratic behavior of hares during the spring mating season, which is often seen as wild or irrational.
2. Is “wacko” a disrespectful term?
“Wacko” is typically used informally and humorously, but it can be seen as disrespectful if used in a mean-spirited way.
3. What does “in a tizzy” mean?
It means to be in a state of confusion, agitation, or distress, often resulting in frantic or irrational behavior.
4. Can “off the deep end” be used in a serious context?
Yes, it can be used seriously to describe someone who is behaving recklessly or without reason, often in response to stress or difficult situations.
5. Are these idioms appropriate for formal writing?
These idioms are best suited for informal writing, conversations, or creative works. They might not be appropriate for professional or academic writing.
Grace Marie is the creator and writer behind Grammer Guru, a platform dedicated to helping people improve their grammar, writing, and communication skills. With a passion for language and a keen eye for detail, Grace provides clear, practical advice on grammar rules, writing techniques, and common linguistic pitfalls.
