disapproval If you call someone a rotter, you are criticizing them because you think that they have behaved in a very unkind or mean way. an unpleasant person who treats other people badly
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'