What does fou mean?
The word "fou" comes from French, where it functions as both an adjective and a noun meaning mad, insane, or crazy — and, in its older sense, a fool or jester. A man described as fou has lost his reason or behaves with wild abandon, while the feminine counterpart is folle. The word extends beyond clinical madness into passionate excess: a fou rire is an uncontrollable fit of laughter, and amour fou denotes obsessive, all-consuming love, a phrase made famous in surrealist art and film. Historically, courts kept professional fools known as fous whose sanctioned madness let them speak truths others could not. Although "fou" itself is not a standard English word, its borrowed phrases appear regularly in English cultural criticism and conversation, making it worth recognising. Anyone encountering it should read it as a marker of madness or extravagant passion rather than as an everyday English term.
In French, a madman or insane person; historically, also a court jester or fool.
"The king's fou entertained the court with jokes no other man would dare to make."
The feminine form of this noun is "folle"; in French grammar the word must agree in gender.
In French, mad, crazy, or insanely wild, whether describing a person's mental state or unrestrained behaviour and emotion.
"She drove at a pace that was simply fou down the coastal road."
As a borrowed French term, "fou" follows French pluralisation: masculine plural "foux," feminine plural "folles." This applies only when using the word in French contexts.
"Both brothers were regarded as foux by the entire village."
The French say "fou" for madman, but the same little word once crowned the most important entertainers in Europe: court jesters were literally called "fous," licensed to be mad on purpose.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fou
"Fou" descends from Latin "follis," which originally meant a bellows or leather bag and came to signify emptiness of mind — hence the Old French "fol" and later "fou," meaning madman or fool. The same Latin root produced related forms across Romance languages, including Italian "folle." The word's association with folly and jest gave medieval Europe its court jesters, often called "fous," and its expressive derivatives like "fou rire" and "amour fou" remain current in modern French.
How fou is actually used
"Fou" is a French word, not part of standard English vocabulary; in English writing it survives almost entirely inside borrowed phrases like "fou rire" and "amour fou." When translating, remember the feminine form is "folle" and agreement matters in French.
Easily confused with fou
"Full" is the ordinary English word for complete or satiated, whereas "fou" is a French word for madness (and, coincidentally, in Scots dialect historically meant drunk); the two share only a superficial sound resemblance.