adjective, rat·ti·er, rat·ti·est.
- full of rats.
- of or characteristic of a rat.
- wretched; shabby: a ratty, old overcoat.
- Slang. irritable or angry; bad-tempered; nasty: I always feel ratty when I wake up.
adjective -tier or -tiest
- British and NZ informal irritable; annoyed
- informal (of the hair) unkempt or greasy
- US and Canadian slang shabby; dilapidated
- Australian slang
- angry
- mad
- of, like, or full of rats
1856, “resembling a rat;” 1865, “full of rats;” 1867, “wretched, miserable, shabby,” from rat (n.) + -y (2).