instant

dilatory, tardy

slow, sluggish

prolonged, protracted

deferred, delayed

incidental, low-pressure, minor, negligible, trivial, unimportant

nonthreatening, safe, stable

coming, future, unborn

completed, concluded, done, ended, finished, over, terminated, through, up

ancient, antediluvian, antiquated, antique, archaic, dated, fusty, musty, obsolete, old, oldfangled, old-fashioned, old-time, out-of-date, outworn, passé

bygone, erstwhile, former, past