Guinea pig

	1.	(Zool.) A small Brazilian rodent (Cavia porcellus or Cavia cobaya), about seven inches in length and usually of a white color, with spots of orange and black. Called also cavy. It is the domesticated form of the wild cavy, often kept as a pet and used commonly as an experimental animal in laboratory research.
	2.	Any animal or person used in an experiment; - also applied to people who are unwillingly or unknowingly subjected by authorities to policies or procedures which might cause bodily or mental harm.
	3.	A contemptuous sobriquet.

Noun	1.	guinea pig - a person who is subjected to experimental or other observational procedures; someone who is an object of investigation; "the subjects for this investigation were selected randomly"; "the cases that we studied were drawn from two different communities" Synonyms: subject, case
	2.	guinea pig - stout-bodied nearly tailless domesticated cavy; often kept as a pet and widely used in research Synonyms: Cavia cobaya

Cape polecat, ape, bar, bear, cavy, chimp, chimpanzee, coon, ferret, foumart, glutton, groundhog, hedgehog, laboratory animal, monk, monkey, mousehound, opossum, patient, polecat, porcupine, possum, prairie dog, quill pig, raccoon, skunk, subject, testee, weasel, whistle-pig, wolverine, woodchuck, zoril