après-midi m, f (plural après-midis)
Traditionally the word was classified as masculine during the last century, but it is recorded as also feminine in the current, ninth edition of the Dictionnaire de l'Académie française (1992). In fact, only the eighth edition (1932-35) recorded it as exclusively masculine. It was recorded as only feminine in the fourth edition (1762) and as both masculine and feminine in the seventh edition (1878). In modern everyday usage it is both feminine and masculine.