overreact

verb

over·​re·​act ˌō-vər-rē-ˈakt 

overreacted; overreacting

intransitive verb

: to react to something too strongly : to respond to something with too strong an emotion or with unnecessary or excessive action

I was furious and yelled at him. He told me I was overreacting and to "chillax."

—Ben Stein

The world isn't coming to an end. You shouldn't overreact to the negative news.

—Adam Bryant

Some of his animals had become apprehensive and twitchy, overreacting to sound or touch …

—Mark Caldwell

But the military police overreacted, using tear gas, rubber bullets and excessive force in front of news cameras that spread the images countrywide.

—Grant Wahl

… the poisonous surfeit of hormones produced by the overreacting immune system.

—Shannon Brownlee

Sometimes companies in a little bit of trouble are the best investments because the market has overreacted.

—Orson C. Clay

overreaction

ˌō-vər-rē-ˈak-shən 

noun

plural overreactions

… he had said almost angrily that he couldn't tell her anything without eliciting a huge overreaction.

—Ann Beattie

This response is an overreaction by your immune system to an otherwise harmless substance, such as pollen or pet dander.

—Medical Clinic Health Letter

Word History

First Known Use

1919, in the meaning defined above

Medical Definition

overreact

intransitive verb

over·​re·​act ˌō-və(r)-rē-ˈakt 

: to react excessively or too strongly

the body's immune system overreacts to the endotoxin

—Tina Adler

overreaction

-ˈak-shən 

noun