Open English Wordnet
Nouns
(n)blink of an eye, flash, heartbeat, instant, jiffy, split second, trice, twinkling, wink, New York minutea very short time (as the time it takes the eye to blink or the heart to beat)“if I had the chance, I'd do it in a flash” Adjectives
(s)instant, instin or of the present month“your letter of the 10th inst” (s)clamant, crying, exigent, insistent, instantdemanding attention“clamant needs”,
“a crying need”,
“regarded literary questions as exigent and momentous” (H.L.Mencken),
“insistent hunger”,
“an instant need”