Agent

noun
  1. A person who acts on behalf of another person or group, typically in a professional capacity. noun
    The actor's agent negotiated a lucrative contract for her latest film.
    As a real estate agent, he helps clients buy and sell properties.
  2. A person or thing that takes an active role or produces a specified effect. noun
    The enzyme acts as a catalyst, serving as an agent in the chemical reaction.
    The government deployed undercover agents to gather intelligence.
  3. A substance that brings about a chemical or physical effect or change. noun
    Bleach is a common cleaning agent used to disinfect surfaces.
    The laboratory tested various agents to determine their effectiveness in breaking down pollutants.
  4. A representative of a government or organization, especially in espionage or law enforcement. noun
    The secret agent infiltrated the enemy's headquarters to obtain classified information.
    FBI agents conducted a raid on the suspect's hideout.