supergrass
🇺🇸
/ˈsuːpərɡræs/
🇬🇧
/ˈsuːpəɡrɑːs/
A person who commits crimes but tells the police about other criminals to get a lighter punishment.
The police arrested the gang after a supergrass revealed their plans.
警察は、スパイが彼らの計画を明らかにした後、ギャングを逮捕しました。