repartee

Short definition from Wiktionary

Noun

1. 1
   A swift, witty reply, especially one that is amusing.
2. 2
   A conversation marked by a series of witty retorts.
3. 3
   A skill in replying swiftly and wittily.

Verb

1. 1
   To reply with a repartee.
2. 2
   To have a repartee (a conversation marked by witty retorts or replies).