adj. & n.
adj. 1 occurring immediately (gives an instant result). 2 a (of food etc.) ready for immediate use, with little or no preparation. b prepared hastily and with little effort (I have no instant solution). 3 urgent; pressing. 4 Commerce of the current month (the 6th instant). 5 archaic of the present moment.
n. 1 a precise moment of time, esp. the present (come here this instant; went that instant; told you the instant I heard). 2 a short space of time (was there in an instant; not an instant too soon). instant replay the immediate repetition of part of a filmed sports event, often in slow motion.
[ ME f. F f. L instare instant- be present, press upon (as IN-(2), stare stand) ]