Possessed of wit; knowing; wise; skillful; judicious; clever; cunning.

Especially, possessing wit or humor; good at repartee; droll; facetious; sometimes, sarcastic; as, a witty remark, poem, and the like.

combining clever conception and facetious expression; "his sermons were unpredictably witty and satirical as well as eloquent"

The Witty worm is a computer worm that attacks the firewall and other computer security products written by a particular company, Internet Security Systems (ISS). It was the first worm to take advantage of vulnerabilities in the very pieces of software designed to enhance network security, and carried a destructive payload, unlike previous worms. It is so named because the phrase "(^.^) insert witty message here (^.^)" appears in the worm's payload.