wean (v.) Look up wean at Dictionary.com
Old English wenian "to accustom, habituate," from Proto-Germanic *wanjan (cognates: Old Norse venja, Dutch wennen, Old High German giwennan, German gewöhnen "to accustom"), from PIE *won-eyo-, from root *wen- (1) "to desire, strive for." The sense of "accustom a child to not suckling from the breast" in Old English was generally expressed by gewenian or awenian, which has a sense of "unaccustom" (compare German abgewöhnen, entwöhnen "to wean," literally "to unaccustom"). The prefix subsequently wore off. Figurative extension to any pursuit or habit is from 1520s.