reactive

adjective

re·​ac·​tive rē-ˈak-tiv How to pronounce reactive (audio)
Synonyms of reactivenext
1
: of, relating to, or marked by reaction or reactance
2
a
: readily responsive to a stimulus
b
: occurring as a result of stress or emotional upset
reactive depression
reactively adverb
reactiveness noun

Examples of reactive in a Sentence

The government's response to the problem was reactive rather than proactive.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Blue Bull transforms Maria Prymachenko’s 1947 painting into a massive UV-reactive mutant vehicle. — Jim Dobson, Forbes.com, 29 Aug. 2026 By being more proactive than reactive, artificial intelligence can spot gaps between global supply chains and patient demand, flagging and addressing issues before pharmacies and hospitals face shortages. — Marc Saltzman, USA Today, 28 Aug. 2026 Another, on Tuesday, came on a reactive attempt to make a play on a ball that ricocheted off of Chisholm’s glove; a rushing Lombard threw it away. — Gary Phillips, New York Daily News, 28 Aug. 2026 This is a dry fabrication technique that uses a chemically reactive plasma to remove material from a substrate. — Ameya Paleja, Interesting Engineering, 27 Aug. 2026 See All Example Sentences for reactive

Word History

First Known Use

1717, in the meaning defined at sense 1

Time Traveler
The first known use of reactive was in 1717

Phrases Containing reactive

Rhymes for reactive

See All Rhymes for reactive

Browse Nearby Words

reactivator
reactive
reactive arthritis
See all Nearby Words

Cite this Entry

“Reactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reactive. Accessed 1 Sep. 2026.

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Kids Definition

reactive

adjective
re·​ac·​tive rē-ˈak-tiv How to pronounce reactive (audio)
1
: of or relating to reaction
2
: reacting or tending to react
reactively adverb
reactiveness noun
reactivity
(ˌ)rē-ˌak-ˈtiv-ət-ē How to pronounce reactive (audio)
noun

Medical Definition

reactive

adjective
re·​ac·​tive rē-ˈak-tiv How to pronounce reactive (audio)
1
a
: of, relating to, or marked by reaction
reactive symptoms
a reactive process
b
: capable of reacting chemically
highly reactive materials
2
a
: readily responsive to a stimulus
the skin of the geriatric is less reactive than that of younger persons—Louis Tuft
b
: occurring as a result of stress or emotional upset especially from factors outside the organism
reactive depression

More from Merriam-Webster on reactive

Thesaurus: All synonyms and antonyms for reactive

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