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

Dogs with higher negative reactivity – fearfulness, for example – responded more to non-animal stimuli like cars and doorbells. —New Atlas, 17 July 2025

This drugstore diamond gently clears buildup without stripping moisture, which is crucial for anyone with dryness or reactivity. —Annie Blackman, Glamour, 14 July 2025

And a decline in estrogen during menopause is also linked to a reduction in emotional reactivity, including anger, says Fosnight. —Lauryn Higgins, Flow Space, 11 July 2025

In forward-thinking clinics like Dr. Bonilla's, patients are experiencing dentistry that goes far beyond fillings: Biocompatible restorations that neutralize ROS and minimize immune reactivity. —Ximena Araya-Fischel, Forbes.com, 4 July 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