Princeton's WordNet

1. rotter, dirty dog, rat, skunk, stinker, stinkpot, bum, puke, crumb, lowlife, scum bag, so-and-so, git(noun)

   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'"