- Overreact is defined as to react in an overly emotional or forceful way.
An example of overreact is someone crying hysterically after accidentally killing an ant.
intransitive verbo·ver·re·act·ed, o·ver·re·act·ing, o·ver·re·acts
(third-person singular simple present overreacts, present participle overreacting, simple past and past participle overreacted)
over- +"Ž react