1831, colloquial, "spirited, courageous," from pluck (n.) in the "courage" sense + -y (2). Related: Pluckily; pluckiness.
Entries linking to plucky
pluck n.
c. 1400, plukke, "a pull, a tug, act of plucking," from pluck (v.). Meaning "courage, boldness, determined energy" (1785), originally in pugilism slang, is a figurative use from the earlier meaning "heart, viscera" (1610s) as that which is "plucked" from slaughtered livestock in preparing the carcass for market. This sense also was perhaps influenced by figurative use of the verb in pluck up (one's courage, etc.), attested from c. 1300.
-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.