spunky (adj.)

1530s, "a spark," Scottish, from Gaelic spong "tinder, pith, sponge," from Latin spongia (see sponge (n.)). The sense of "courage, pluck, mettle" is first attested 1773. A similar sense evolution took place in cognate Irish sponnc "sponge, tinder, spark; courage, spunk." Vulgar slang sense of "seminal fluid" is recorded from c. 1888.

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.