informant

thumb|right|240px|A representative from the United States Department of State |U.S. State Department congratulates and offers a partial payment to a fully disguised informant whose information led to the neutralization of a terrorist in the Philippines thumb|Two-page totally confidential, direct and immediate letter from the Iranian Minister of Finance to the Minister of Foreign Affairs (Hossein Fatemi) about creating a foreign information network for controlling smuggling, 15 December 1952

An informant (also called an informer or, as a slang term, a "snitch", "rat", "canary", "stool pigeon", "stoolie", "tout" or "grass", among other terms) is a person who provides privileged information, or (usually damaging) information intended to be intimate, concealed, or secret, about a person or organization to an agency, often a government or law enforcement agency. The term is usually used within the law-enforcement world, where informants are officially known as confidential human sources (CHS), or criminal informants (CI). It can also refer pejoratively to someone who supplies information without the consent of the involved parties. The term is commonly used in politics, industry, entertainment, and academia.