reply vs answer

reply and answer both are nouns.

Word	Noun	Adjective	Verb	Adverb
reply	Yes	No	Yes	No
answer	Yes	No	Yes	No

As nouns, answer is a hyponym of reply; that is, answer is a word with a more specific, narrower meaning than reply:

As nouns, reply and answer are synonyms defined as:

reply and answer: a statement (either spoken or written) that is made to reply to a question or request or criticism or accusation

Other synonyms of reply include response.

As verbs, reply and answer are synonyms defined as:

Other synonyms of reply include respond.

reply (noun)	answer (noun)
the speech act of continuing a conversational exchange	a nonverbal reaction
a statement (either spoken or written) that is made to reply to a question or request or criticism or accusation	the speech act of replying to a question
	a statement (either spoken or written) that is made to reply to a question or request or criticism or accusation
	a statement that solves a problem or explains how to solve the problem
	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

reply (verb)	answer (verb)
react verbally	give the correct answer or solution to
	respond to a signal
	understand the meaning of
	react to a stimulus or command
	react verbally
	give a defence or refutation of (a charge) or in (an argument)
	be satisfactory for; meet the requirements of or serve the purpose of
	match or correspond
	be liable or accountable
	be sufficient; be adequate, either in quality or quantity