muhbir

مُخْبِر، وَاشٍ

1. Someone who brings news. (dated)
2. Someone who reports a problem or violation to the authorities; informant, whistle-blower.
3. Someone who leaks confidential information in a company to its rivals; informant, telltale, rat.
4. Someone who relays information of misconduct to hurt others, especially out of spite; blabbermouth, snitch. (slang)