WordNet sense 1 (a very short time (as the time it takes the eye blink or the heart to beat)):

flash, heartbeat, jiffy, trice, twinkling, wink, blink of an eye, New York minute, split second

WordNet sense 2 (a particular point in time):

minute, moment, second, minute

WordNet sense 3 (in or of the present month):

inst

WordNet sense 4 (temporal sense; intermediate between past and future; now existing or happening or in consideration):

present

WordNet sense 5 (occurring with no delay):

instantaneous

WordNet sense 6 (acting or moving or capable of acting or moving quickly):

fast

WordNet sense 7 (demanding attention):

crying, exigent, insistent, clamant

WordNet sense 8 (requiring attention or action):

imperative