SQUEALER
hog, pig, grunter, squealer, Sus scrofa
(noun) domestic swine
informer, betrayer, rat, squealer, blabber
(noun) one who reveals confidential information in return for money
Source: WordNet® 3.1
Etymology
Noun
squealer (plural squealers)
Any animal or person who squeals.
A pig.
(slang) An informant.
Anything that makes a squealing noise.
The European swift.
The harlequin duck.
The American golden plover.
A young pigeon.
Source: Wiktionary
Squeal"er, n.
1. One who, or that which, squeals.
2. (Zoöl.)
(a) The European swift.
(b) The harlequin duck.
(c) The American golden plover.
Source: Webster’s Unabridged Dictionary 1913 Edition