Something heard through the grapevine

RUMOR

This often spreads quickly but isn’t always based on facts—think of whispered talk that might not be true.

The phrase "through the grapevine" is a common idiom meaning information passed informally from person to person, often without confirmation. Since a rumor is an unverified piece of news spread this way, the clue cleverly hints at the answer by referencing how gossip travels. It’s a straightforward play on the idea of hearsay, where "grapevine" directly ties to the concept of rumors.