means Forceful and lively in a vigorous, attention-grabbing way — said of writing, speech, or style that packs a strong impact in a small space.

from From the noun "punch," a blow with the fist, which goes back to the verb "punch" (to strike or pierce), itself a 14th-century borrowing from Old French "poinçonner," to prick or stamp, ultimately from Latin "pungere," to puncture — the same root that gives us "point" and "puncture." The "-y" suffix turned the fist's blow into a quality of vigor; "punchy" meaning "snappy and forceful" is a fairly recent flowering, though the same word also carries a boxer's irony: a "punchy" fighter is one made groggy by taking too many hits.