fiancée

Affidavit refers to a written promise, and its Latin roots connect it to another kind of promise in English. It comes from a past tense form of the Latin verb affidare, meaning “to pledge”; in Latin, affidavit translates to “he or she has made a pledge.”

Affidare is also the root of affiance, an archaic English noun meaning “trust, faith, confidence,” “marriage contract or promise,” or a meaning that has completely fallen from use, “close or intimate relationship.” More familiar to modern English speakers is the verb affiance, meaning “to promise in marriage” or “to betroth.” It usually appears as a fancy-sounding participial adjective:

I like to give affianced friends a copy of Rebecca Mead’s book “One Perfect Day,” which exposes the ridiculous wedding industry.
—Mollie Hemingway, The Federalist, 7 October 2014

Affiance came through French to English in the 14th century, and, nearly 500 years later, the related French words fiancé and fiancée were added to English. Etymologically speaking, a fiancé or fiancée is a “promised one.”

People may well be anxious, when referring to their betrothed, to make sure that they use the correct term. So the fact that fiancé and fiancée are pronounced exactly the same may cause some degree of worry and uncertainty. These two words are borrowed directly from French, in which language they have equivalent but gendered meanings: fiancé refers to a man who is engaged to be married, and fiancée refers to a woman. We have, as of this date, no evidence suggesting that the meaning of either word is affected by the gender of the person to whom the fiancé or fiancée is engaged.