1640s, "full of tangles," from snarl (n.1) + -y (2). By 1798 as "irritable, cross."
Entries linking to snarly
snarl n.1
late 14c., "a snare, noose, trap," perhaps a diminutive of snare (n.1) with -el (2). The meaning "a tangle, a knot" in hair, thread, etc. is attested from c. 1600. That of "traffic jam" is from 1933.
-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.