ratter
NounWordNet 3.0
Webster's Dictionary (GCIDE)
Ratter \Rat"ter\ (r[a^]t"t[~e]r), n.
1.One who, or that which, rats, as one who deserts his party. [1913 Webster]
2.Anything which catches rats; esp., a dog trained to catch rats; a rat terrier. See Terrier. [1913 Webster]