WordNet (r) 3.0 (2006):

sell out
    v 1: get rid of all one's merchandise [syn: sell out, sell
         up, liquidize]
    2: give information that compromises others

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "sell out":
   apostatize, bear witness against, beguile, betray, blab,
   blow the whistle, bolt, break away, bunk, clear the trade,
   close out, convert, convert into cash, cross, cut under, defect,
   delude, desert, double-cross, dump, effect a sale, fink,
   four-flush, humbug, inform against, inform on, job, let down,
   liquidate, make a sale, market, merchandise, mislead, move, narc,
   peach, pull out, rat, resell, retail, run out on, sacrifice,
   secede, sell, sell off, sell on consignment, sell over,
   sell retail, sell short, sell up, sell wholesale, snitch,
   snitch on, split, squeal, stool, take in, tattle, tell on,
   terminate the account, testify against, turn in, turn informer,
   turn into money, turn over, two-time, undercut, undersell, unload,
   wholesale