Definitions
1.NounAny tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
A domestic guinea pig, Cavia porcellus, often kept as a pet.
2.NounA domestic guinea pig, Cavia porcellus, often kept as a pet.
3.NounA living experimental subject."He became a human guinea pig and was paid by the company."
4.NounA professional company director, without time or real qualifications for the duties.
5.NounA midshipman in the East India service; a low-skilled or non-proficient seaman.