acting; exerting power (opposed to patient).

verb (used with object)

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 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for counteragent

Historical Examples of counteragent

  • It would serve F right if they perfected a counteragent first.

  • Good Lord, it might have contained a counteragent that could have killed me!

    A Knyght Ther Was

    Robert F. Young

  • If I had a counteragent to the grass ready I would not be wasting time talking to reporters.

  • I am on the way to develop the counteragent, but to advance further I need to make tests upon the living grass itself.

  • PM on the wireless with the assurance a counteragent will be perfected within the week.

British Dictionary definitions for counteragent



a person who acts on behalf of another person, group, business, government, etc; representative
a person or thing that acts or has the power to act
a phenomenon, substance, or organism that exerts some force or effecta chemical agent
the means by which something occurs or is achieved; instrumentwind is an agent of plant pollination
a person representing a business concern, esp a travelling salesman
British short for estate agent
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 counteragent



1610s, from agent (n.).



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.

Online Etymology Dictionary, © 2010 Douglas Harper

counteragent in Medicine




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.

counteragent in Science



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.