Definition of "joust"

A tilting match: a mock combat between two mounted knights or men-at-arms using lances in the lists or enclosed field.  examples

To engage in mock combat on horseback, as two knights in the lists; to tilt.  examples

To engage in verbal sparring over an important issue. (used of two people, both of whom participate more or less equally)  examples

(slang) To touch penises while engaging in a sex act, especially oral sex.