An ugly person who has a lack of personal hygiene and/or has had alot of sexual partners. Usually used to describe females.
1. Nick: "Did you shag that bird
last night mate?
Dez: "Yes mate! She was a reight ratter!"
2. "Stay away from her mate, she's a right ratter."
3. "Errrrgh....You Ratter! Dirty rat-bag!"