crazy
KRAY-zee
Crazy (adj) means Mentally unstable or irrational; behaving in a wild or nonsensical way. Example: “The noise from the building site was driving me crazy.”
adj
1
Mentally unstable or irrational; behaving in a wild or nonsensical way.
"The noise from the building site was driving me crazy."
"It would be crazy to quit your job without any savings."
"He went crazy trying to fix the printer for the third time that day."
2
Informal: extremely enthusiastic about or infatuated with someone or something.
"My brother is crazy about football and watches every match he can."
"They were crazy about each other from the day they met."
"She's crazy about horror movies."
noun
1
Informal: an eccentric or irrational person.
"Don't listen to him, he's just a crazy."
How to use crazy
Learner’s notesIn plain EnglishWildly irrational, or (informally) very enthusiastic or infatuated.
When to use it
Very common in casual speech; avoid in clinical or formal contexts describing actual mental illness, where it can sound dismissive.
Common pairings
crazy about
drive someone crazy
go crazy
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Word forms
- Plural
- crazies
- Comparative
- crazier, more crazy
- Superlative
- craziest, most crazy
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The noise from the building site was driving me _____.
Etymology
From craze ("to crack or shatter") plus -y — the idea of a mind that has "cracked" led to the modern meaning of insane or wildly irrational.
Synonyms
View more →Antonyms
Related words
Rhymes for crazy
See all rhymes for crazy →Frequently asked questions
What does “crazy” mean?
The word “crazy” means mentally unstable or irrational; behaving in a wild or nonsensical way. In plain terms, wildly irrational, or (informally) very enthusiastic or infatuated.
How do you pronounce “crazy”?
“Crazy” is pronounced KRAY-zee (/ˈkɹeɪ.zi/ in IPA).
How do you use “crazy” in a sentence?
Here is “crazy” used in a sentence: “It would be crazy to quit your job without any savings.”
What part of speech is “crazy”?
Depending on how it is used, “crazy” can be an adjective and a noun.
Is “crazy” a common word?
“Crazy” is a very common word in modern English, usually learned at around the A2 level.
How many meanings does “crazy” have?
“Crazy” has 3 distinct senses listed in this dictionary. The most common is: mentally unstable or irrational; behaving in a wild or nonsensical way.
Is 'crazy' an offensive word?
It can be. In casual speech, crazy often just means wild, chaotic or irrational and passes without offence. But when used to describe people with mental-health conditions, it is widely seen as insensitive and stigmatising. In those contexts, respectful, specific language is preferred over the word crazy.
What is the difference between 'crazy' and 'insane'?
Both informally describe wild or irrational behaviour and often swap freely. Insane sounds stronger and more extreme, and it also has a formal legal meaning about mental capacity. Crazy is the more casual, everyday word. Neither is appropriate as a clinical description of genuine mental illness.
Can 'crazy' be used in a positive way?
Yes. Informally, crazy often works as an enthusiastic intensifier rather than an insult: 'crazy good,' 'crazy talented,' or 'the view was crazy.' Saying you're 'crazy about' someone or something means you love it. Here crazy signals extreme degree or excitement, not instability.
Is 'crazy' formal or informal?
Crazy is informal. It fits everyday conversation, texts and casual writing, but not formal, professional or clinical settings. In serious contexts, plainer words like irrational, unreasonable or reckless are clearer and safer, and specific medical terms are used instead when describing genuine mental-health conditions.
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