I. adjective
no longer active or in use
obsolete social customs
Synonyms: dead, disused, extinct, outmoded, outworn, passé, superseded; compare ancient 1
Related Word: old-fashioned, old hat, old-time, old-timey, out-of-date, unfashionable; dusty, fusty, moldy, moth-eaten, musty, stale, timeworn
Idioms: behind the times
Contrasted words: contemporary, modern, new-fashioned, up-to-date, up-to-the-minute; novel, original, unique
Antonyms: current
II. verb
Synonyms: outdate , antiquate, obsolesce, outmode, superannuate