instant

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"

a particular point in time; "the moment he arrived the party began"

occurring with no delay; "relief was instantaneous"; "instant gratification"

in or of the present month; "your letter of the 10th inst"

demanding attention; "clamant needs"; "a crying need"; "regarded literary questions as exigent and momentous"- H.L.Mencken; "insistent hunger"; "an instant need"