Noun

1. A statement (either spoken or written) that is made to reply to a question or request or criticism or accusation
2. A statement that solves a problem or explains how to solve the problem
3. The speech act of replying to a question
4. The principal pleading by the defendant in response to plaintiff's complaint; in criminal law it consists of the defendant's plea of `guilty' or `not guilty' (or nolo contendere); in civil law it must contain denials of all allegations in the plaintiff's complaint that the defendant hopes to controvert and it can contain affirmative defenses or counterclaims
5. A nonverbal reaction

Verb

1. React verbally
2. Respond to a signal
3. Give the correct answer or solution to
4. Understand the meaning of
5. Give a defence or refutation of (a charge) or in (an argument)
6. Be liable or accountable
7. Be sufficient; be adequate, either in quality or quantity
8. Match or correspond
9. Be satisfactory for; meet the requirements of or serve the purpose of
10. React to a stimulus or command