guinea pig

plural guinea pigs · alternative guinea-pig · alternative Guinea-pig · alternative Guinea pig · alternative guineapig

1. Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
   1. especiallyA domestic guinea pig, Cavia porcellus, often kept as a pet.

      Synonyms: cavy, domestic cavy, domestic guinea pig

2. figurativelyA living experimental subject.

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

   2 more examples

   [H]e spoke of the unwisdom of volunteering one's services as a guinea pig.

   1970, Larry Niven, Ringworld, page 115

   My dad told me about his days in the Navy: He'd agreed to be a guinea pig in exchange for a shorter enlistment. They kept him awake for a week straight.

   2008 October, Davy Rothbart, “How I caught up with dad”, in Men's Health, volume 23, number 8, →ISSN, page 112

   Synonyms: lab rat

3. datedslangA professional company director, without time or real qualifications for the duties.
4. obsoletenauticalA midshipman in the East India service; (by extension) a low-skilled or non-proficient seaman.

   A good seaman he is... none of your guinea-pigs.

   1748, Tobias Smollett, The Adventures of Roderick Random, page 183

   1 more example

   I promise you, to me it was no slight penance to be exposed during the whole voyage to the half sneering, satirical looks of the mates and guinea-pigs.

   1779, Macintosh, Travels, quoted in Carey, Old Days, i. 73