U.S. slang prefix, by 1836 as che-, 1843 as ker-, possibly from influence of German or Dutch ge-, past participial prefixes; or ultimately echoic of the sound of the fall of some heavy body.
cavort v.
1793, cauvaut, "to prance, bustle nimbly or eagerly," American English, of uncertain origin, sometimes said to be an alteration of curvet "a leap by a horse," a word from French that is related to curve (v.). Or perhaps from ca-, ka-, colloquial intensive prefix + vault (v.) "to jump, leap." Modern form attested by 1829. Related: Cavorted; cavorting.