| v. t. | 1. | To act or perform a second time; to do over again; to reenact; |
| v. i. | 1. | To return an impulse or impression; to resist the action of another body by an opposite force; |
| 2. | To act upon each other; to exercise a reciprocal or a reverse effect, as two or more chemical agents; to act in opposition. |
| Verb | 1. | react - show a response or a reaction to something Synonyms: respond |
| 2. | react - undergo a chemical reaction; react with another substance under certain conditions; "The hydrogen and the oxygen react" | |
| 3. | react - act against or in opposition to; "She reacts negatively to everything I say" Synonyms: oppose |