foul play

foul play
    n 1: unfair or dishonest behavior (especially involving
         violence)
    

52 Moby Thesaurus words for "foul play":
      artifice, assassination, blood, bloody murder, bumping-off,
      chicane, chicanery, collusion, connivance, connivery, conspiracy,
      covin, crime, deception, dirty pool, dirty trick, dirty work,
      dodgery, double-dealing, duplicity, elimination, falseheartedness,
      foul, guile, hanky-panky, homicide, killing, liquidation,
      machination, manslaughter, murder, perfidiousness, perfidy,
      pettifoggery, pettifogging, purge, purging, removal,
      sharp practice, skulduggery, sleight, supercherie, thuggee,
      thuggery, thuggism, treacherousness, treachery, trickery,
      underhand dealing, unfairness, unsportsmanlikeness,
      unsportsmanliness