instant

nouns

a 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"
New York minute, blink of an eye, flash, heartbeat, instant, jiffy, split second, trice, twinkling, wink
a particular point in time
"the moment he arrived the party began"
instant, minute, moment, second
is derived from
instantaneous

adjectives

occurring with no delay
"relief was instantaneous"; "instant gratification"
instant, instantaneous
is derived from
instancy
in or of the present month
"your letter of the 10th inst"
inst, instant
demanding attention
"clamant needs"; "a crying need"; "regarded literary questions as exigent and momentous"- H.L.Mencken; "insistent hunger"; "an instant need"
clamant, crying, exigent, insistent, instant
is derived from
instancy