verb (used with object), ac·ti·vat·ed, ac·ti·vat·ing.
  1. to make active; cause to function or act.
  2. Physics.
    1. to render more reactive; excite: to activate a molecule.
    2. to induce radioactivity.
  3. to aerate (sewage) in order to accelerate decomposition of impure organic matter by microorganisms.
  4. Chemistry.
    1. to make (carbon, a catalyst, molecules, etc.) more active.
    2. to hasten (reactions) by various means, as heating.
  5. to place (a military unit or station) on an active status in an assigned capacity.

Origin of activate

First recorded in 1620–30; active + -ate1
Related formsac·ti·va·tion, nounnon·ac·ti·va·tion, nouno·ver·ac·ti·vate, verb (used with object), o·ver·ac·ti·vat·ed, o·ver·ac·ti·vat··per·ac·ti·vate, verb (used with object), su·per·ac·ti·vat·ed, su·per·ac·ti·vat·ing.un·ac·ti·vat·ed, adjective
Can be confusedactivate actuate stimulate

Synonyms for activate

1. actuate, start, turn on, set going.

Antonyms for activate Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for overactivate


verb (tr)
  1. to make active or capable of action
  2. physics to make radioactive
  3. chem
    1. to increase the rate of (a reaction)
    2. to treat (a substance, such as carbon or alumina) so as to increase powers of adsorption
  4. physiol to prepare by arousal (the body or one of its organs (e.g. the brain)) for action
  5. to purify (sewage) by aeration
  6. US military to create, mobilize, or organize (a unit)
Derived Formsactivation, nounactivator, noun
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 overactivate



1620s; see active + -ate (2). Related: Activated; activating.

Online Etymology Dictionary, © 2010 Douglas Harper