inert

UK: /ɪnˈɜː^rt/ US: /ɪnˈɝt/ ,(in ûrt′, i nûrt′)

WordReference Random House Learner's Dictionary of American English © 2025

in•ert /ɪnˈɜrt/   adj. 

1. having no power of action (opposed to active):
   inert matter.
2. Chemistry (of chemical substances) having little or no ability to react in a chemical reaction:
   Nitrogen is an inert gas.
3. inactive or sluggish:
   He stood inert as we rushed toward her.

in•ert•ly, adv. 
in•ert•ness, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

in•ert  (in ûrt′, i nûrt′), adj. 

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

• Latin inert- (stem of iners) unskillful, equivalent. to in- in-³ + -ert-, combining form of art- (stem of ars) skill; see art¹
• 1640–50

in•ert′ly, adv. 
in•ert′ness, n. 
Synonyms

• 1. immobile, unmoving, lifeless, motionless.
• 4. See inactive. 

Collins Concise English Dictionary © HarperCollins Publishers::

inert / ɪnˈɜːt/ adjective

1. having no inherent ability to move or to resist motion
2. inactive, lazy, or sluggish
3. having only a limited ability to react chemically; unreactive

Etymology: 17th Century: from Latin iners unskilled, from in-¹ + ars skill; see art¹

inˈertly adverb

inˈertness noun