Source : WordNet®

dirty dog
     n : a person who is deemed to be despicable or contemptible;
         "only a rotter would do that"; "kill the rat"; "throw the
         bum out"; "you cowardly little pukes!"; "the British call
         a contemptible person a `git'" [syn: {rotter}, {rat}, {skunk},
          {stinker}, {stinkpot}, {bum}, {puke}, {crumb}, {lowlife},
          {scum bag}, {so-and-so}, {git}]