Fink

(n) A person who is not trustworthy. One who will snitch on friends and is unreliable. An individual with a smaller than normal penis, often accompanied by poor sexual prowess and a general disposition of lethargy and laziness. Shifty in nature and socially awkward. A human version of a sloth.

I thought he has my back but that fink told my boss I fucked his wife. He then fucked my sister but she said she could hardly feel that fink.