The Collaborative International Dictionary of English v.0.48:

Punchy \Punch"y\, a. [Perhaps for paunchy, from paunch. See 3d
   Punch.]
   Short and thick, or fat.
   [1913 Webster] Punctated

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "punchy":
   acid, bedazzled, biting, corrosive, cutting, dazed, dazzled, dopey,
   driving, effective, forceful, forcible, groggy, gutsy, imperative,
   impressive, in a daze, incisive, knocked silly, mazed, mordant,
   nervous, penetrating, piercing, poignant, powerful, punch-drunk,
   sensational, silly, sinewed, sinewy, slaphappy, slashing, striking,
   strong, telling, trenchant, vigorous, vital, woozy