"accustomed, usual," c.1400, past participle adjective from wont. An unconscious double past participle.
"accustomed," Old English wunod, past participle of wunian "to dwell, be accustomed," from Proto-Germanic *wun- "to be content, to rejoice" (cf. Old Saxon wunon, Old Frisian wonia "to dwell, remain, be used to," Old High German wonen, German wohnen "to dwell;" related to Old English winnan, gewinnan "to win" (see win) and to wean. The noun meaning "habitual usage, custom" is attested from c.1300.