See more synonyms for agent on
  1. a person or business authorized to act on another's behalf: Our agent in Hong Kong will ship the merchandise. A best-selling author needs a good agent.
  2. a person or thing that acts or has the power to act.
  3. a natural force or object producing or used for obtaining specific results: Many insects are agents of fertilization.
  4. an active cause; an efficient cause.
  5. a person who works for or manages an agency.
  6. a person who acts in an official capacity for a government or private agency, as a guard, detective, or spy: an FBI agent; the secret agents of a foreign power.
  7. a person responsible for a particular action: Who was the agent of this deed?
  8. Grammar. a form or construction, usually a noun or noun phrase, denoting an animate being that performs or causes the action expressed by the verb, as the police in The car was found by the police.
  9. Indian agent.
  10. a representative of a business firm, especially a traveling salesperson; canvasser; solicitor.
  11. Chemistry. a substance that causes a reaction.
  12. Pharmacology. a drug or chemical capable of eliciting a biological response.
  13. Pathology. any microorganism capable of causing disease.
  14. British. a campaign manager; an election agent.
  1. acting; exerting power (opposed to patient).
verb (used with object)
  1. to represent (a person or thing) as an agent; act as an agent for: to agent a manuscript; Who agented that deal?

Origin of agent

1570–80; < Latin agent- (stem of agēns (present participle) doing), equivalent to ag- (root of agere to do) + -ent- -ent
Related formscoun·ter·a·gent, nounin·ter·a·gent, nounsu·per·a·gent, nounun·der·a·gent, noun

Synonyms for agent

See more synonyms for on Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for agent

Contemporary Examples of agent

Historical Examples of agent

British Dictionary definitions for agent


  1. a person who acts on behalf of another person, group, business, government, etc; representative
  2. a person or thing that acts or has the power to act
  3. a phenomenon, substance, or organism that exerts some force or effecta chemical agent
  4. the means by which something occurs or is achieved; instrumentwind is an agent of plant pollination
  5. a person representing a business concern, esp a travelling salesman
  6. British short for estate agent
  7. short for secret agent
Derived Formsagential (eɪˈdʒɛnʃəl), adjective

Word Origin for agent

C15: from Latin agent-, noun use of the present participle of agere to do
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for agent

late 15c., "one who acts," from Latin agentem (nominative agens) "effective, powerful," present participle of agere "to set in motion, drive, lead, conduct" (see act (n.)). Meaning "any natural force or substance which produces a phenomenon" is from 1550s. Meaning "deputy, representative" is from 1590s. Sense of "spy, secret agent" is attested by 1916.


1610s, from agent (n.).

Online Etymology Dictionary, © 2010 Douglas Harper

agent in Medicine


  1. A force or substance, such as a chemical, that causes a change.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

agent in Science


  1. A substance that can bring about a chemical reaction or a biological effect. Compare reagent.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.