From Longman Dictionary of Contemporary Englishreactre‧act /riˈækt/ ●●● S3 W3 AWL verb [intransitive] 1 behaviour/feelingsREACT to behave in a particular way or show a particular emotion because of something that has happened or been said → respondreact to How did Wilson react to your idea? He reacted angrily to the suggestion that he had lied. She reacted very badly (=was very upset) when her parents split up. You have to react quickly to circumstances.react by doing something The government reacted by declaring all strikes illegal. → overreact2 chemicals technicalHC if a chemical substance reacts, it changes when it is mixed with another chemical substancereact with The calcium reacts with sulphur in the atmosphere.3 prices if prices or financial markets react to something that happens, they increase or decrease in value because of itreact to Oil prices reacted sharply (=reacted a lot) to news of the crisis in the Middle East. The market reacted favourably to the announcement.4 become illMI to become ill when a chemical or drug goes into your body, or when you eat a particular kind of food → respondreact to Quite a lot of children react badly to antibiotics.COLLOCATIONSadverbsreact badly (=become annoyed, upset etc)Do you react badly to criticism?react angrily/violentlyThe prime minister reacted angrily to these accusations.react stronglyScott reacted strongly when he felt he was being treated unjustly.react quickly/swiftlyThe goalkeeper had to react quickly.react differentlyPeople react differently to stress.react positively/negatively (=with positive/negative emotions or opinions)We want versatile people who react positively to change.react cautiously (=carefully, so that you avoid danger or risk)The United States has reacted cautiously to the offer.react instinctively (=without thinking or needing to think)She reacted instinctively and reached for her gun. → react against something→ See Verb table
Examples from the Corpusreact• How will your best friend react?• Emma is not behaving very reasonably nowadays. I think she's reacting against her teachers' strictness.• Ned reacted angrily to Bill's comments.• The chairman reacted angrily to the report and said it would make it much harder to reach a deal.• Foam began to spread through the air as the fire-fighting systems reacted automatically to the emergency.• It's hard not to react badly when your kids are playing up.• A shot was fired, and the police reacted by firing into the crowd.• Nobody reacts much when older men become fathers.• Suddenly, before the competition could react, Snapple was in stores all across the country.• Cool foresight and a quick mind enabled him to react swiftly in an emergency.• The authorities reacted swiftly with a smear counterattack.• People reacted to the speech in different ways.• Only two persons in the audience reacted to this sentence, but to them it was like being doused with ice-cold water.• Investors reacted unfavorably to the announcement and pushed shares down as much as 3. 9 percent.• How did Dad react when he found out Vicky was pregnant?• How did she react when you told her the news?• How did your parents react when you told them you were going to marry Jim?• When children perform poorly at school, parents often react with anger.• Many gays reacted with outrage at the tactic of "outing" senior public figures.react to• The patient reacted badly to penicillin.• Residents reacted angrily to the city council's decision.reacted sharply• Critics of the reforms reacted sharply last night.react badly• Chances were she would react badly.• Some mares react badly and their reproductive cycles cease or are disrupted.• Do you react badly to criticism at work?• Bird lovers reacted badly to earlier attempts to control the birds by poisoning them and removing nests.• They don't like it too hot in summer and they react badly to over-watering.• Others began to react badly to various chemicals at about the time they developed candidiasis.• But it reacted badly when he started on examples of government action to extend opportunity.