rat vs ratter

rat and ratter both are nouns.

Word	Noun	Adjective	Verb	Adverb
rat	Yes	No	Yes	No
ratter	Yes	No	No	No

rat (noun)	ratter (noun)
any of various long-tailed rodents similar to but larger than a mouse	any of several breeds of terrier developed to catch rats
a pad (usually made of hair) worn as part of a woman's coiffure	a disloyal person who betrays or deserts his cause or religion or political party or friend etc.
a person who is deemed to be despicable or contemptible
someone who works (or provides workers) during a strike
one who reveals confidential information to the police or other authority

rat (verb)	ratter (verb)
give away information about somebody
catch rats, especially with dogs
give (hair) the appearance of being fuller by using a rat
desert one's party or group of friends, for example, for one's personal advantage
take the place of work of someone on strike
employ scabs or strike breakers in