1660s, from streak (n.) + -y (2). Related: Streakiness.
Entries linking to streaky
streak n.
Old English strica "line of motion, stroke of a pen" (related to strican "pass over lightly"), from Proto-Germanic *strikon- (source also of Middle Dutch streke, Dutch streek, Middle Low German streke "a stroke, line," Old High German, German strich, Gothic striks "a stroke, line"), from PIE root *strig- "to stroke, rub, press" (see strigil; also compare strike (v.), stroke (v.)). Sense of "long, thin mark" is first found 1560s. Meaning "a temporary run (of luck)" is from 1843.
-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.