fait accompli, a

A deed or action already completed. The term is French for “accomplished action” and was adopted into English in the early nine- teenth century. The French critic Nicolas Boileau, exponent of the classical style, may have been one of the first to popularize the term in French, in his treatise L’Art poétique (1674), expounding the classic unities of drama:
“Qu’en un lieu, qu’en un jour, un seul fait accompli tienne jusqu’à la fin le théâtre rempli” (One place, one time, one single action will keep the audience in the theater to the end).