1. Not active or tending to be active: inactive students at risk for gaining weight.
a. Not functioning or operating; out of use: inactive machinery.
b. Not being in continuous use or operation: an inactive brokerage account.
3. Retired from duty or service: inactive military personnel.
4. Chemistry Not readily participating in chemical reactions; inert.
5. Medicine Marked by the absence or lessening of disease activity.
6. Physics Showing no optical activity in polarized light.
in′ac·tivi·ty, in·active·ness n.
Synonyms: inactive, idle, inert, dormant, latent, quiescent
These adjectives mean not involved in or disposed to movement or activity. Inactive indicates absence of activity: retired but not inactive; an inactive factory. Idle refers to persons who are not doing anything or are not busy: employees who were idle because of the strike. It also refers to what is not in use or operation: idle machinery. Inert describes things powerless to move themselves or to produce a desired effect; applied to persons, it implies lethargy or sluggishness, especially of mind or spirit: "The Honorable Mrs. Jamieson ... was fat and inert, and very much at the mercy of her old servants" (Elizabeth C. Gaskell).
Dormant refers to a state of suspended activity but often implies the possibility of renewal: dormant feelings of affection. What is latent is present but not evident: latent ability. Quiescent sometimes—but not always—suggests temporary inactivity: "For a time, he [the whale] lay quiescent" (Herman Melville).
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.