Synonyms

react

American

[ree-akt] / riˈækt /

verb (used without object)

to act in response to an agent or influence.

How did the audience react to the speech?
to act reciprocally upon each other, as two things.
to act in a reverse direction or manner, especially so as to return to a prior condition.
to act in opposition, as against some force.
to respond to a stimulus in a particular manner.

reacting to a shock by jumping; to react to the word “coward” with anger.
to undergo a chemical reaction.

react British

/ rɪˈækt /

verb

(intr; foll by to, upon etc) (of a person or thing) to act in response to another person, a stimulus, etc, or (of two people or things) to act together in a certain way
to act in an opposing or contrary manner
(intr) physics to exert an equal force in the opposite direction to an acting force
chem to undergo or cause to undergo a chemical reaction

"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

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Etymology

Origin of react

First recorded in 1635–45; re- + act, probably modeled on Medieval Latin reagere

Explanation

When you react to something, you respond to it. If someone pokes you in class, you might react by sticking out your tongue at them. The teacher might then react by giving you both detention. If someone says to you, "act, don't react," they are telling you not to automatically respond to something that someone does. Instead, you should think about it first and then decide what you want to do. In science, the word react is used to describe what happens when two substances combine and cause a chemical change in each other. When you add baking soda to vinegar, the chemicals in each react and create a foamy lava like substance.

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Vocabulary lists containing react

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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.

Warsh himself has called for removing the Fed's forward guidance messaging altogether, arguing that it locks policymakers into a position rather than allowing them to react to changing situations.

From Barron's • Jun. 17, 2026

Bosnia-Herzegovina left-back Sead Kolasinac did not react quickly enough in Toronto.

From BBC • Jun. 13, 2026

“War of the Worlds” laid the groundwork Spielberg builds upon with “Disclosure Day,” analyzing how humans react when events beyond their control instantly remove their autonomy.

From Salon • Jun. 13, 2026

Wrobleski limped away, finally able to react to the pain where the ball hit him.

From Los Angeles Times • Jun. 12, 2026

Before I could react, the planks in the bulkhead to my right split apart, and Tarrypin—his shell bundled in chains—was marched out.

From "Tristan Strong Punches a Hole in the Sky" by Kwame Mbalia

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023