"biting, sharp," 1898, colloquial, in reference to a "biting" chill in the air, from nip (n.2) + -y (2). Related: Nippiness.
Entries linking to nippy
nip n.2
"a pinch; a sharp bite," 1540s, from nip (v.). Sense of "a small bit of anything, fragment or bit pinched off" is from c. 1600. Meaning "a chill in the weather" is from 1610s, probably so called for its effect on vegetation. Nip and tuck "a close thing," especially a close approach to equality in the results of a horse race or any competition, is recorded by 1847, American English, perhaps an image from sailing or tailoring.
-y 2
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.