late 14c., enfourmer "instructor, teacher," native agent noun from inform and also from Old French enformeor. Meaning "one who gives information against another" (especially in reference to law-breaking) is c. 1500.
权威例句
1. Prentice saw Goss fall in behind the informer.
普伦蒂斯看见戈斯走在密探身后。
2. The police provided a safe house for the informer.
警方给线人提供了一个安全屋.
3. One of the gang members had turned informer.
团夥中的一员后来变成了告密者.
4. The gang leader decided that the informer must be taken for a ride.
歹徒头目决定要将告密者用汽车绑架去干掉.
5. He could always claim Sollozzo was an informer he was meeting.