The Collaborative International Dictionary of English v.0.48:

Gallivant \Gal"li*vant\, v. i. [From Gallant.]
   To play the beau; to wait upon the ladies; also, to roam
   about for pleasure without any definite plan. [Slang]
   --Dickens.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gallivant
    v 1: wander aimlessly in search of pleasure [syn: gallivant,
         gad, jazz around]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "gallivant":
   bat, bat around, bum, cast coquettish glances, coquet, count ties,
   divagate, drift, eye, flirt, flit, gad, gad about, go about,
   go the rounds, gold-dig, hit the road, hit the trail, hobo, jaunt,
   knock about, knock around, look sweet upon, make eyes at, meander,
   mooch, nomadize, ogle, peregrinate, pererrate, philander,
   play around, prowl, ramble, range, roam, rove, run about,
   run around, saunter, straggle, stray, stroll, traipse, tramp,
   vagabond, vagabondize, walk the tracks, wander, wayfare