a particular point in time
"the moment he arrived the party began"
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"
- blink of an eye - split second - new york minute
"a crying need"
"regarded literary questions as exigent and momentous"- H.L.Mencken
"an instant need"
in or of the present month
"your letter of the 10th inst"
occurring with no delay
"relief was instantaneous"