Crazy can mean anything from wild and fun to completely out of control. Whether describing someone’s quirky behavior or extreme emotions, these idioms capture the many shades of “crazy.”

1. Mad as a Hatter

Meaning: Completely insane or eccentric.
Example: “Ever since he won the lottery, he’s been mad as a hatter.”
Tone: Playful, exaggerated.
Other ways to say it: Loopy, out of one’s mind.

2. Off One’s Rocker

Meaning: Acting irrationally or foolishly.
Example: “If you think I’m working 24 hours straight, you must be off your rocker.”
Tone: Colloquial, humorous.
Other ways to say it: Out of one’s mind, losing it.

3. Nuts About Something

Meaning: Extremely enthusiastic or obsessed.
Example: “She’s nuts about horror movies and watches them every weekend.”
Tone: Fun, lighthearted.
Other ways to say it: Crazy for, obsessed with.

4. Lose One’s Marbles

Meaning: To become mentally unstable.
Example: “He’s been working so hard that he might lose his marbles soon.
Tone: Concerned, informal.
Other ways to say it: Go insane, crack up.

5. Batty as a Belfry

Meaning: Totally crazy or eccentric.
Example: “That inventor is as batty as a belfry, but his ideas are genius.”
Tone: Quirky, old-fashioned.
Other ways to say it: Wacky, peculiar.

6. Barking Mad

Meaning: Completely crazy or irrational.
Example: “Spending that much on a handbag? That’s barking mad!”
Tone: British, informal.
Other ways to say it: Nuts, bonkers.

7. One Sandwich Short of a Picnic

Meaning: A little crazy or not very bright.
Example: “He’s nice, but he’s one sandwich short of a picnic.”
Tone: Funny, teasing.
Other ways to say it: Not all there, a few screws loose.

8. Bonkers

Meaning: Totally crazy or irrational.
Example: “The way they decorated their house is absolutely bonkers.”
Tone: Casual, fun.
Other ways to say it: Nuts, off the wall.

9. A Few Screws Loose

Meaning: A little mentally unstable or eccentric.
Example: “I like her, but she definitely has a few screws loose.”
Tone: Playful, judgmental.
Other ways to say it: Not quite right, off-kilter.

10. Gone Off the Deep End

Meaning: Acting extremely irrationally.
Example: “After his breakup, he went off the deep end for a while.”
Tone: Dramatic, serious.
Other ways to say it: Lost control, lost his mind.

11. Crazy Like a Fox

Meaning: Appearing foolish but actually very clever.
Example: “Don’t underestimate him; he’s crazy like a fox.”
Tone: Witty, insightful.
Other ways to say it: Cleverly deceptive, cunning.

12. As Mad as a March Hare

Meaning: Completely mad or unpredictable.
Example: “He’s as mad as a March hare when it comes to conspiracy theories.”
Tone: Playful, whimsical.
Other ways to say it: Wild, unpredictable.

13. Out of One’s Mind

Meaning: Extremely crazy or irrational.
Example: “You’re out of your mind if you think I’m running 10 miles with you.”
Tone: Dramatic, emphatic.
Other ways to say it: Insane, nuts.

14. Around the Bend

Meaning: Mentally unstable or behaving strangely.
Example: “The stress of finals week is driving me around the bend.”
Tone: Lighthearted, conversational.
Other ways to say it: Losing it, going crazy.

15. Wacko

Meaning: Acting bizarrely or irrationally.
Example: “That guy’s conspiracy theories are completely wacko.”
Tone: Slang, informal.
Other ways to say it: Nuts, bonkers.

16. Not Playing with a Full Deck

Meaning: Not thinking clearly or acting foolishly.
Example: “If he thinks that’s a good idea, he’s not playing with a full deck.”
Tone: Amusing, slightly critical.
Other ways to say it: Not all there, missing a few screws.

17. Off the Wall

Meaning: Unusual or eccentric.
Example: “His fashion choices are really off the wall, but I love them.”
Tone: Playful, quirky.
Other ways to say it: Outrageous, unconventional.

18. Stark Raving Mad

Meaning: Totally and uncontrollably crazy.
Example: “If she sees the mess we made, she’ll go stark raving mad!”
Tone: Exaggerated, dramatic.
Other ways to say it: Completely insane, utterly mad.

19. Cuckoo

Meaning: Silly or crazy.
Example: “He’s totally cuckoo for starting a business during a recession.”
Tone: Playful, informal.
Other ways to say it: Loony, wacky.

20. Fit to be Tied

Meaning: Extremely angry or upset.
Example: “Mom was fit to be tied when she saw the broken window.”
Tone: Dramatic, intense.
Other ways to say it: Furious, out of control.

21. Flip One’s Lid

Meaning: Lose one’s temper or act irrationally.
Example: “She flipped her lid when she found out about the surprise.”
Tone: Expressive, informal.
Other ways to say it: Lose it, blow up.

22. Off in La-La Land

Meaning: Not paying attention or lost in daydreams.
Example: “During the meeting, he was off in La-La Land.”
Tone: Whimsical, light.
Other ways to say it: Spaced out, daydreaming.

23. Blow a Fuse

Meaning: To suddenly become very angry.
Example: “Dad blew a fuse when I dented his car.”
Tone: Intense, serious.
Other ways to say it: Lose one’s temper, freak out.

24. Go Bananas

Meaning: To act wild with excitement or madness.
Example: “The crowd went bananas when the band came on stage.”
Tone: Playful, fun.
Other ways to say it: Go wild, freak out.

25. Loony Bin

Meaning: A mental hospital or a place of chaos.
Example: “With five kids running around, my house feels like a loony bin.”
Tone: Humorous, exaggerated.
Other ways to say it: Mad house, asylum.

26. Wild Goose Chase

Meaning: A pointless, crazy pursuit.
Example: “Trying to find that rare book felt like a wild goose chase.”
Tone: Frustrating, humorous.
Other ways to say it: Hopeless search, chasing a dream.

27. Climbing the Walls

Meaning: Restless or going stir-crazy.
Example: “After a week of rain, the kids were climbing the walls.”
Tone: Frustrated, exaggerated.
Other ways to say it: Going stir-crazy, losing patience.

Conclusion

From quirky to completely unhinged, these idioms capture the different ways people describe craziness in everyday language.