[in-urt, ih-nurt]


having no inherent power of action, motion, or resistance (opposed to active): inert matter.
Chemistry. having little or no ability to react, as nitrogen that occurs uncombined in the atmosphere.
Pharmacology. having no pharmacological action, as the excipient of a pill.
inactive or sluggish by habit or nature.

Origin of inert

1640–50; < Latin inert- (stem of iners) unskillful, equivalent to in- in-3 + -ert-, combining form of art- (stem of ars) skill; see art1
Related formsin·ert·ly, adverbin·ert·ness, nounnon·in·ert, adjectivenon·in·ert·ly, adverbnon·in·ert·ness, nounun·in·ert, adjectiveun·in·ert·ly, adverb

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

Examples from the Web for inert

Contemporary Examples of inert

Historical Examples of inert

  • Johnny Rosenfeld still lay in his ward, inert from the waist down.


    Mary Roberts Rinehart

  • And when bending over that inert face I felt that there was no longer any breath!

    My Double Life

    Sarah Bernhardt

  • The chauffeur got down, shook his fare by the arm, and the arm was inert.

    A Nest of Spies

    Pierre Souvestre

  • There he saw the inert figures of the girl, and Tom Franklin.

    The World Beyond

    Raymond King Cummings

  • An atom of any kind is not the inert thing it has been supposed to be, for it can do something.

    The Machinery of the Universe

    Amos Emerson Dolbear

British Dictionary definitions for inert



having no inherent ability to move or to resist motion
inactive, lazy, or sluggish
having only a limited ability to react chemically; unreactive
Derived Formsinertly, adverbinertness, noun

Word Origin for inert

C17: from Latin iners unskilled, from in- 1 + ars skill; see art 1
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 inert

1640s, from French inerte (16c.) or directly from Latin inertem (nominative iners) "unskilled, inactive, helpless, sluggish, worthless," from in- "without" + ars (genitive artis) "skill" (see art (n.)). Originally of matter; specifically of gases from 1885. Of persons or creatures, from 1774.

Online Etymology Dictionary, © 2010 Douglas Harper

inert in Medicine




Sluggish in action or motion; lethargic.
Not readily reactive with other chemical elements; forming few or no chemical compounds.
Having no pharmacologic or therapeutic action.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

inert in Science



Not chemically reactive.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.