An overreaction is a reaction that is too strong or too much. Sometimes people use the word to describe a reaction that is not really appropriate.
The school district overreacted when they canceled the class.
The police department overreacted when they shot the suspect.
noun
an excessive reaction; a reaction with inappropriate emotional behavior
1
The government was scared and overreacted and banned the banquet.
2
I apologize for my impertinence and overreaction as well.
3
Being enoyed and paranoiac by the first, I overreacted on the second.
4
Rules are rules, but overreaction is overreaction.
5
It was in no way an overreaction.
6
This seems to be an overreaction.
7
Don't overreact to this situation.
8
Is not suitable, but let's not overreact.
9
Definitely an exercise on premature overreaction.
10
Deleting it was very much an overreaction.