Other forms: overreacting, overreacted, overreacts
To overreact is to respond far more strongly than a thing deserves. Don't overreact, he overreacted, overreacting again.
It is nearly always said by somebody else, and telling a person they are overreacting is one of the more inflammatory things available in English. Institutions overreact too, and the pattern after a rare disaster is well documented. Note overreaction; and that the over- is doing exactly the work it looks like it is doing.
1verboverreactTo respond far more strongly than a thing deserves.
“Don't overreact; it's only a small scratch on the car.”
overreact is an excessive response.
From over- + react.
Etymology from Wiktionary, CC BY-SA