Synonyms of weasels

1 Syllable
narc, fink, snitch, sneak, nark, rat
2 Syllables
stoolie, squealer, tattler, tipster, snitcher, betrayer, source, turncoat
3 Syllables
blabbermouth, canary, deceiver, informer, informant
4 Syllables
tattletale, whistle-blower, double-crosser