Old English wenian "to accustom," from Proto-Germanic *wanjanan (cf. Old Norse venja, Dutch wennen, Old High German giwennan, German gewöhnen "to accustom"), from *wanaz "accustomed" (related to wont). The sense of weaning a child from the breast in Old English was generally expressed by gewenian or awenian, which has a sense of "unaccustom" (cf. German abgewöhnen, entwöhnen "to wean," literally "to unaccustom"). The prefix subsequently wore off. Figurative extension to any pursuit or habit is from 1520s.