fink
n. countable C2 Proficiency US //ˈfɪŋk// UK //fˈɪŋk// fink
n. someone who tells a secret to the police or a boss to get others in trouble. It is a very negative word for a person who betrays their friends or group.
n. an informer or someone who betrays a group's secrets to an authority figure. Often carries a strong pejorative connotation of disloyalty within a social or criminal circle.
Nobody likes a fink who tells on their friends.
The gang suspected there was a fink among them after the police arrived exactly when the shipment was delivered.
In the high-stakes world of corporate espionage, being labeled a fink can end a career more quickly than any official legal reprimand ever could.
Usage
Informal and derogatory; frequently used in mid-20th century American English contexts.