excuse vs explain

excuse is a noun but explain is not a noun.

Word	Noun	Adjective	Verb	Adverb
excuse	Yes	No	Yes	No
explain	No	No	Yes	No

As verbs, excuse and explain are synonyms defined as:

excuse (noun)	explain (noun)
a poor example
a defense of some offensive behavior or some failure to keep a promise etc.
a note explaining an absence

excuse (verb)	explain (verb)
accept an excuse for	make plain and comprehensible
defend, explain, clear away, or make excuses for by reasoning	define
excuse, overlook, or make allowances for; be lenient with	serve as a reason or cause or justification of
serve as a reason or cause or justification of
grant exemption or release to
ask for permission to be released from an engagement