c.1200, "to be lacking," from Old Norse vanta "to lack, want," earlier *wanaton, from Proto-Germanic *wanen, from PIE *we-no-, from root *eue- "to leave, abandon, give out" (see vain). The meaning "desire, wish for" is first recorded 1706. Related: wanted; wanting.
c.1300, "deficiency, shortage," from Old Norse vant, neuter of vanr "wanting, deficient;" related to Old English wanian "to diminish" (see wane). Phrase for want of is recorded from c.1400. Meaning "state of destitution" is recorded from mid-14c. Newspaper want ad is recorded from 1897. Middle English had wantsum (c.1200) "in want, deprived of," literally "want-some."