answer vs reply

answer and reply both are nouns.

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

As nouns, reply is a hypernym of answer; that is, reply is a word with a broader meaning than answer:

Other hypernyms of answer include response.

As nouns, answer and reply are synonyms defined as:

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

Other synonyms of answer include response.

As verbs, answer and reply are synonyms defined as:

Other synonyms of answer include respond.

answer (noun)	reply (noun)
a nonverbal reaction	the speech act of continuing a conversational exchange
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 (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

answer (verb)	reply (verb)
give the correct answer or solution to	react verbally
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