react

verb

re·​act rē-ˈakt 

reacted; reacting; reacts

intransitive verb

1

: to exert a reciprocal or counteracting force or influence

—often used with on or upon

2

: to change in response to a stimulus

3

: to act in opposition to a force or influence

—usually used with against

4

: to move or tend in a reverse direction

5

: to undergo chemical reaction

transitive verb

: to cause to react

Synonyms

• reply
• respond

Examples of react in a Sentence

When I told her what happened, she reacted with anger.

I didn't expect him to react that way.

The firefighters reacted quickly when they heard the alarm.

He reacted badly to the drug.

Recent Examples on the Web

Then in 2008, the West did not react to Russia’s war in Georgia. —Stephan Kieninger / Made By History, TIME, 30 Oct. 2024

Fans reacted to the news with glee, declaring that Durk is one of the realest rappers out right now. —Marc Griffin, VIBE.com, 30 Oct. 2024

Brady reacted to the news by posting an Instagram story that felt a little emotional. —Lissete Lanuza Sáenz, StyleCaster, 29 Oct. 2024

Bad Bunny reacted swiftly to Sunday’s comments—made by Tony Hinchcliffe at New York’s Madison Square Garden, in what was framed as a comedy set—by sharing a clip on social media from the Kamala Harris campaign, outlining her plans for Puerto Rico. —Jazz Monroe, Pitchfork, 29 Oct. 2024

Word History

Etymology

New Latin reactus, past participle of reagere, from Latin re- + agere to act — more at agent

First Known Use

1644, in the meaning defined at intransitive sense 1

Phrases Containing react

• react against

Kids Definition

react

verb

re·​act rē-ˈakt 

1

: to act or behave in response (as to stimulation or an influence)

the colonists reacted to the tax by boycotting tea

2

: to oppose a force or influence

—usually used with against

reacted against their unfair treatment

3

: to go through or cause to go through a chemical reaction

Medical Definition

react

intransitive verb

re·​act rē-ˈakt 

1

: to respond to a stimulus

2

: to undergo chemical reaction

transitive verb

: to cause to react