What does bonkers mean?
"Bonkers" is an informal adjective meaning utterly crazy, mad, or absurd. It is applied both to people behaving irrationally and, more commonly today, to ideas, plans, prices, or situations that are ludicrously extreme or unreasonable — a scheme might be described as "totally bonkers" even if everyone involved is perfectly sane. The word originated in British English in the mid-twentieth century, most likely deriving from the verb "bonk," meaning to strike, so its underlying image may be that of someone knocked senseless by a blow to the head. Though it began as a colloquialism, it has spread widely through popular culture and is now readily understood across the English-speaking world. It carries a playful, affectionate connotation rather than a clinical one: calling someone bonkers usually signals exasperated amusement rather than genuine concern about mental health. Common collocations include "go bonkers" (to become wildly excited or angry) and intensifying phrases such as "stark raving bonkers" and "utterly bonkers." Because of its informal tone, it suits conversation, journalism, and comedy far better than formal or academic prose.
adjectiveCompletely crazy or absurd; wildly irrational or out of one's mind. Used informally to describe people, ideas, or situations that are ludicrously extreme.
- Utterly crazy or mad; mentally deranged (informal).
- Absurdly excessive or unreasonable; wildly implausible (informal).
- (Of a person) extremely excited or enthusiastic — e.g. the crowd went bonkers.
"Paying five hundred pounds for a concert ticket seemed utterly bonkers to her."
"My neighbour goes bonkers every time a pigeon lands on his balcony."
"The plot of the film was completely bonkers, but somehow it worked."
'Bonkers' likely grew out of 'bonk' — a word for a blow to the head — so calling someone bonkers may once have implied they'd been knocked silly.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bonkers
"Bonkers" first appeared in British slang in the mid-twentieth century. Its most widely accepted origin is the older verb "bonk," meaning to hit or strike, suggesting the adjective originally evoked someone rendered senseless by a blow to the head. It gained broader currency through British popular culture and later spread to American English, where it remains recognisably informal.
How bonkers is actually used
Informal register only — inappropriate in formal writing. Originally British English but now widely understood in American usage. Almost always used affectionately or humorously; describing someone as bonkers rarely carries serious clinical weight.
Easily confused with bonkers
The verb 'bonk' means to hit something (or, in British slang, to have sex), while 'bonkers' as an adjective means crazy or mad.