1) Bad egg 2) Cad 3) Cur 4) Git 5) Louse 6) Lowlife 7) Puke 8) Skunk 9) Stinker 10) Stinkpot 1) Bounder 2) British bad guy 3) Cad finds river animal 4) Crumb 5) Dirty dog 6) Disagreeable person 7) Heel 8) London lowlife 9) Lowlife 10) Puke 11) Scum bag 12) Skunk 13) Stinker 14) Stinkpot 15) Sussex scoundrel 16) Unpleasant person 
Rotter is British slang for a worthless, unpleasant, or despicable person
[n] - a person who is deemed to be despicable or contemptible
dirty dog 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``