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

Abnormal 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

Examples of reactivity in a Sentence

Recent Examples on the Web

In oxygen’s case, its outermost shell is two electrons short — comparatively fewer than other elements — and the configuration of those electrons contribute to oxygen’s high reactivity. —Laura Poppick, Rolling Stone, 30 June 2025

Orange also developed canine reactivity, which the couple worked on with a professional dog trainer. —Melissa Fleur Afshar, MSNBC Newsweek, 22 May 2025

The biggest takeaway for me is that proactivity leads to less reactivity. —Georgia Godfrey, Forbes, 21 Jan. 2025

This outdated mentality fosters two counterproductive patterns: emotional repression, in which individuals suppress feelings, and emotional reactivity, where feelings are expressed impulsively and without regulation. —Andriana Eliadis, Forbes.com, 20 June 2025

Word History

First Known Use

1832, in the meaning defined above

Phrases Containing reactivity

• hyper-reactivity

Rhymes for reactivity

• absorptivity
• affectivity
• collectivity
• conductivity
• connectivity
• corrosivity
• creativity
• diffusivity
• directivity
• effectivity
• emissivity
• exclusivity

Medical Definition

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