maintainer vs maintain

maintainer is a noun but maintain is not a noun.

Word	Noun	Adjective	Verb	Adverb
maintainer	Yes	No	No	No
maintain	No	No	Yes	No

maintainer (noun)	maintain (noun)
someone who upholds or maintains

maintainer (verb)	maintain (verb)
	stick to correctly or closely
	state categorically
	state or assert
	support against an opponent
	maintain by writing regular records
	supply with necessities and support
	keep in safety and protect from harm, decay, loss, or destruction
	have and exercise
	maintain for use and service
	cause to continue in a certain state, position, or activity