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Synonyms

reactive

American  
[ree-ak-tiv] / riˈæk tɪv /

adjective

  1. tending to react.

  2. pertaining to or characterized by reaction.

  3. Electricity. pertaining to or characterized by reactance.


reactive British  
/ rɪˈæktɪv, ˌriːækˈtɪvɪtɪ /

adjective

  1. readily partaking in chemical reactions

    sodium is a reactive metal

    free radicals are very reactive

  2. of, concerned with, or having a reactance

  3. responsive to stimulus

  4. (of mental illnesses) precipitated by an external cause

    reactive depression

"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

Other Word Forms

Etymology

Origin of reactive

First recorded in 1705–15; react + -ive

Explanation

To be reactive is to be ready to react or respond to something else — as opposed to ready to act on one's own. A person who's reactive does things only in response to others. To react is to do something in response to something else. When someone pinches you, for example, you react. But if you're a reactive person, then you only react; you're always ready to react but not to act on your own. You're rather lifeless unless something or someone else causes you to do act. This is usually seen as a negative trait in people, unless you're talking about, say, firefighters or cops. We admire people who don't need prodding to get things done. Some chemicals are called reactive, too, because they react readily with other chemicals.

Keep Reading on Vocabulary.com

Vocabulary lists containing reactive

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Reactive force field models are relatively common, but they usually require training for specific reaction types.

From Science Daily • Mar. 7, 2024

Ambient.ai emerged from stealth mode last year with $52 million in funding and the tag line “From Reactive to Proactive.”

From Slate • Dec. 11, 2023

Reactive oxygen molecules flood the lungs, and the extra bilirubin may help counteract their effects, Horsfall says.

From Science Magazine • Jun. 8, 2023

Reactive platforms like Twitter are today’s “Jerry Springer” and Kirkus Reviews rolled into one.

From Los Angeles Times • Mar. 6, 2020

Reactive changes in the vicinity of tuberculous joints are of common occurrence, and play a considerable part in the production of what is clinically known as white swelling.

From Manual of Surgery Volume First: General Surgery. Sixth Edition. by Thomson, Alexis