Gossip is idle talk or rumor, especially about the personal or private affairs of others; the act is also known as dishing or tattling.
One winds on the distaff what the other spins (Both spread gossip) by Pieter Bruegel the Elder
This Soviet war poster conveys the message: "Don't chatter! Gossiping borders on treason" (1941).
The Friendly Gossips (1901) by Eugene de Blaas
A rumor, or rumour, is "a tall tale of explanations of events circulating from person to person and pertaining to an object, event, or issue in public concern."
A 1930s Works Progress Administration poster depicts a man with WPA shovel attacking a wolf labeled 'rumor'.