WordNet (r) 3.0 (2006):

step out
    v 1: go outside a room or building for a short period of time

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "step out":
   carouse, cast off, celebrate, cut loose, debauch, doff, douse,
   drop, hell around, jollify, jolly, lark, let go, let loose,
   let off steam, make merry, make whoopee, put off, raise hell,
   remove, revel, roister, see life, skylark, slip out of, spree,
   step out of, take off, throw off, undo, unwrap, wanton,
   whoop it up