reactivity
noun
re·ac·tiv·i·ty
(ˌ)rē-ˌak-ˈti-və-tē 
: the quality or state of being reactive
emotional reactivity
chemical reactivity
If the brain, responding to psychological stress, stimulates the release of cortisol and cortisol suppresses the reactivity of the immune system, then a dormant viral infection may well flare up, or a new one catch hold.—
Matt Ridley
Matt RidleyAbnormal reactivity to light and abnormal pupillary size may be important clues to the presence of cranial injury in the setting of head trauma.—Bradford J. Shingleton
Bradford J. ShingletonExamples of reactivity in a Sentence
Recent Examples on the Web
Exaggerated cortisol reactivity to stress has been associated with poor long-term health.
—New Atlas, 21 Aug. 2025
This ad-hoc approach can lead to over-reactivity, too.
—Leila Saad, Forbes.com, 20 Aug. 2025
The website PetMD says that leash training keeps a dog safe in public, can prevent leash reactivity, and also allows pups to go more places with their owner if they are conditioned to being on a leash.
—Alyce Collins, MSNBC Newsweek, 19 Aug. 2025
By proving that cyclocarbons can be stabilised in a bottle at room temperature, the work opens the door to exploring their chemical reactivity, optical behaviour and potential technological applications.
—Neetika Walter, Interesting Engineering, 15 Aug. 2025
See All Example Sentences for reactivity
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New Atlas, 21 Aug. 2025
This ad-hoc approach can lead to over-reactivity, too.
—Leila Saad, Forbes.com, 20 Aug. 2025
The website PetMD says that leash training keeps a dog safe in public, can prevent leash reactivity, and also allows pups to go more places with their owner if they are conditioned to being on a leash.
—Alyce Collins, MSNBC Newsweek, 19 Aug. 2025
By proving that cyclocarbons can be stabilised in a bottle at room temperature, the work opens the door to exploring their chemical reactivity, optical behaviour and potential technological applications.
—Neetika Walter, Interesting Engineering, 15 Aug. 2025
See All Example Sentences for reactivity
Cite this Entry
“Reactivity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reactivity. Accessed 9 Sep. 2025.
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reactivity
noun
re·ac·tiv·i·ty
(ˌ)rē-ˌak-ˈtiv-ət-ē
plural reactivities
: the quality or state of being reactive
skin reactivity
emotional reactivity
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