What does crazy mean?
Crazy is an informal English adjective with several related senses. Its oldest use describes someone who is mentally deranged or insane, though this application is now widely regarded as insensitive when aimed at people with actual mental illness. More commonly today it means wild, absurd, or wildly impractical — a crazy plan, a crazy idea — or expresses intense enthusiasm, as in being crazy about someone or something. It can even serve as an informal intensifier, as in 'crazy busy.' The word derives from the verb 'craze,' which originally meant to shatter or crack, so its earliest sense referred to things that were cracked or flawed rather than minds. Common idioms include 'drive someone crazy,' 'go crazy,' and working 'like crazy.' Because of its flexibility and emotional charge, crazy is one of the most versatile — and most casually overused — words in everyday English.
Mentally deranged; insane.
"He started acting crazy after days without sleep."
Considered stigmatizing when applied to people with mental illness; prefer precise, respectful language in serious contexts.
Extremely enthusiastic or infatuated.
"They're crazy about each other."
Foolish, impractical, or wildly unreasonable.
"It would be crazy to hike up that mountain in winter without gear."
Informal, usually pluralized: a mentally unstable person.
"The asylum was full of what they then called the crazies."
Derogatory; best avoided except when quoting historical usage.
Used only for the rare noun sense referring to unstable people; derogatory and generally avoided in modern usage.
"The tabloid headline dismissed the protesters as a bunch of crazies."
Before it ever described a person's mind, "crazy" literally meant full of cracks — like broken porcelain.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of crazy
Crazy comes from the verb "craze," which entered Middle English in the 14th century from Old Norse "krasa," meaning to shatter or break. Originally, "crazy" described objects that were cracked, flawed, or fragile — a sense still echoed in "crazy quilt." The meaning shifted by the late 16th and early 17th centuries to describe unsound health and then unsound minds, giving rise to the modern senses of insanity and, later, wild enthusiasm or absurdity.
Related word forms
How crazy is actually used
Predominantly informal; in clinical or formal contexts, terms like 'mental illness' are preferred over calling someone crazy. When applied to people, it can be considered stigmatizing. In casual American English it also works as an adverbial intensifier ('crazy good').
Easily confused with crazy
"Craze" is the noun or verb meaning a short-lived fashion or to develop fine cracks, while "crazy" is the adjective describing madness, enthusiasm, or absurdity.