late 15c., from Old French viril, from Latin virilis "of a man, manly," from vir "a man, a hero," from PIE *uiHro "freeman" (cf. Sanskrit virah, Avestan vira-, Lithuanian vyras, Lithuanian vyras, Old Irish fer, Welsh gwr, Gothic wair, Old English wer "man"). Virile member for "penis" is recorded from 1540s.