'Loser' definitions:

Definition of 'loser'

From: WordNet
noun
A contestant who loses the contest [syn: loser, also- ran] [ant: victor, winner]
noun
A person with a record of failing; someone who loses consistently [syn: failure, loser, nonstarter, unsuccessful person] [ant: achiever, succeeder, success, winner]
noun
A gambler who loses a bet [ant: winner]

Definition of 'Loser'

From: GCIDE
  • Loser \Los"er\, n.
  • 1. One who loses; as, the loser pays for a round of beer. --South. [1913 Webster]
  • 2. A person who is habitually unsuccessful at some endeavor, such as employment or personal relationships. [slang] [PJC]
  • 3. A plan or strategy unlikely to succeed. [slang] [PJC]

Synonyms of 'loser'

From: Moby Thesaurus