crazy

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.

“Crazy” is pronounced KRAY-zee (/ˈkɹeɪ.zi/ in IPA).

Here is “crazy” used in a sentence: “It would be crazy to quit your job without any savings.”

Depending on how it is used, “crazy” can be an adjective and a noun.

“Crazy” is a very common word in modern English, usually learned at around the A2 level.

“Crazy” has 3 distinct senses listed in this dictionary. The most common is: mentally unstable or irrational; behaving in a wild or nonsensical way.

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.

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.

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.

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.