Source : Webster's Revised Unabridged Dictionary (1913)

Defeat \De*feat"\, v. t. [imp. & p. p. {Defeated}; p. pr. & vb.
   n. {Defeating}.] [From F. d['e]fait, OF. desfait, p. p. ofe
   d['e]faire, OF. desfaire, to undo; L. dis- + facere to do.
   See {Feat}, {Fact}, and cf. {Disfashion}.]
   1. To undo; to disfigure; to destroy. [Obs.]

            His unkindness may defeat my life.    --Shak.

   2. To render null and void, as a title; to frustrate, as
      hope; to deprive, as of an estate.

            He finds himself naturally to dread a superior Being
            that can defeat all his designs, and disappoint all
            his hopes.                            --Tillotson.

            The escheators . . . defeated the right heir of his
            succession.                           --Hallam.

            In one instance he defeated his own purpose. --A. W.
                                                  Ward.

   3. To overcome or vanquish, as an army; to check, disperse,
      or ruin by victory; to overthrow.

   4. To resist with success; as, to defeat an assault.

            Sharp reasons to defeat the law.      --Shak.

   Syn: To baffle; disappoint; frustrate.

Source : WordNet®

defeated
     adj 1: beaten or overcome; not victorious; "the defeated enemy"
            [ant: {undefeated}]
     2: disappointingly unsuccessful; "disappointed expectations and
        thwarted ambitions"; "their foiled attempt to capture
        Calais"; "many frustrated poets end as pipe-smoking
        teachers"; "his best efforts were thwarted" [syn: {disappointed},
         {discomfited}, {foiled}, {frustrated}, {thwarted}]
     n : people who are defeated; "the Romans had no pity for the
         defeated" [syn: {discomfited}]