From Longman Dictionary of Contemporary Englishchumpchump /tʃʌmp/ noun [countable] 1 STUPID/NOT SENSIBLE informal someone who is silly or stupid, and who is easily deceived2 → chump chop/steak
Examples from the Corpus
chump• I mean, a chump who spends an entire three-hour train ride returning voice mail?• Stockbrokers, politicians and company chairmen hanker after retail investors for the same, simple reason: they think they are chumps.• The big chump didn't know what to do.• This is a fine time for Mum to go off her chump, he said to himself as he began his walk.• From literal chump to deserving champ.• From national champs to national chumps.• Caldecott was the epitome of the public school chump that Nick detested.• None of that circus water Loretta dished us out when the chumps were buying.Origin chump (1800-1900) chump “thick piece of wood” ((18-19 centuries)), perhaps from chunk + lump 