Reddit reviews Sins of the Tongue:: The Backbiting Tongue

Gossip has two sides, detraction and calumny.

Detraction is telling something true about someone that shouldn't be told, especially when doing so damages one's name and reputation (journalism, court trials, and things like are exceptions to that). Calumny is inventing lies about someone.

Gossip injures three people at the same time: the person gossiping, the person who listens to the gossip, and the person gossiped about.

Read up on in Sins of the Tongue: The Backbiting Tongue.

Fr Belet says that gossip kills three people: the person spreading the gossip, the person listening to the gossip, and the person being gossiped about.