reactive
Americanadjective
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tending to react.
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pertaining to or characterized by reaction.
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Electricity. pertaining to or characterized by reactance.
adjective
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readily partaking in chemical reactions
sodium is a reactive metal
free radicals are very reactive
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of, concerned with, or having a reactance
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responsive to stimulus
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(of mental illnesses) precipitated by an external cause
reactive depression
Other Word Forms
Etymology
Origin of reactive
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.
Vocabulary lists containing reactive
Chemical Reactions - Introductory
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Matter and Energy 2: Properties of Matter, Chemical Reactions, and Energy
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The State of the Union Address 2015
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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.
“The only path forward is strict licensing, real-time enforcement, and consequences that actually hurt. Reactive letters won’t fix this. The industry needs to move at the speed of AI — not the speed of litigation.”
From Los Angeles Times • Feb. 18, 2026
Reactive separations combine chemical reactions with purifying separations and can provide process intensification, converting the non-fossil carbon more efficiently.
From Science Daily • May 1, 2024
Reactive oxygen molecules flood the lungs, and the extra bilirubin may help counteract their effects, Horsfall says.
From Science Magazine • Jun. 8, 2023
Reactive metals such as iron, lead, and aluminum almost always bond to other elements and are rarely found in a native state.
From Textbooks • Jan. 1, 2017
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
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
