instant

1 done or occurring without any noticeable lapse in time an instant response to the cry for help Synonyms immediate, instantaneous, split-second, straightawayRelated Words summary; fast, hit-and-run, prompt, quick, rapid, speedy, swiftNear Antonyms dilatory, tardy; slow, sluggish; prolonged, protracted; deferred, delayed

2 needing immediate attention an instant need for food supplies in the famine-stricken country Synonyms burning, clamant, compelling, critical, crying, dire, emergent, exigent, imperative, imperious, importunate, acute, necessitous, pressing, urgentRelated Words demanding, extreme, immediate, insistent, intense, overriding; crucial, desperate, grave, life-and-death (also life-or-death), serious, severe, vital; dangerous, explosive, hazardous, perilous, precarious, unstableNear Antonyms incidental, low-pressure, minor, negligible, trivial, unimportant; nonthreatening, safe, stableAntonyms noncritical, nonurgent

3 existing or in progress right now we should be more concerned with instant dangers than with those in the far-off future Synonyms current, extant, immediate, present, ongoing, present-dayRelated Words contemporary, mod, modern, modernistic, new, newfangled, new-fashioned, recent, red-hot, space-age, supermodern, ultramodern, up-to-date; being, breathing, existent, existing, livingNear Antonyms coming, future, unborn; completed, concluded, done, ended, finished, over, terminated, through, up; ancient, antediluvian, antiquated, antique, archaic, dated, fusty, musty, noncontemporary, obsolete, old, oldfangled, old-fashioned, old-time, out-of-date, outworn, passé; ago, bygone, erstwhile, former, past