Meaning of AGENT in English

adj acting;

— opposed to patient, or sustaining, action.

2. agent ·noun one who exerts power, or has the power to act; an actor.

3. agent ·noun one who acts for, or in the place of, another, by authority from him; one intrusted with the business of another; a substitute; a deputy; a factor.

4. agent ·noun an active power or cause; that which has the power to produce an effect; as, a physical, chemical, or medicinal agent; as, heat is a powerful agent.

Webster English vocab.      Английский словарь Webster.