FINK

FINK is an internet slang term/abbreviation used to describe someone who informs or betrays others, particularly in online communities.

Examples:
1.

Person A: Did you see that person revealing our secret strategies to the opposing team?

Person B: Yeah, what a fink! We can’t trust them anymore.

2.

Comment on a forum post:

• “I shared a personal story seeking advice, and someone took screenshots of it and spread it around. They’re such finks for violating my privacy.”