also guinea-pig
( guinea pigs)
1.
If someone is used as a guinea pig in an experiment, something is tested on them that has not been tested on people before.
...a human guinea pig...
Nearly 500,000 pupils are to be guinea pigs in a trial run of the new 14-plus exams.
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2.
A guinea pig is a small furry animal without a tail. Guinea pigs are often kept as pets.
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