cavy

noun

1. 1

   A tailless rodent of the family Caviidae and the genus Cavia, with short ears and larger than a hamster; the species Cavia porcellus is often kept as a pet.

2. 2

   A rodent of any of several species within the family Caviidae.

3. 3

   A living experimental subject.

   “He became a human guinea pig and was paid by the company.”

4. 4

   A professional company director, without time or real qualifications for the duties.

5. 5

   A midshipman in the East India service; (by extension) a low-skilled or non-proficient seaman.