Nouns

(n)fink, snitch, snitcher, stoolpigeon, stool pigeon, stoolie, sneak, sneaker, canarysomeone acting as an informer or decoy for the police
(n)canarya female singer
(n)canary yellow, canarya moderate yellow with a greenish tinge
(n)canary, canary birdany of several small Old World finches

Adjectives

(s)canary, canary-yellowhaving the color of a canary; of a light to moderate yellow