maintain vs conserve

maintain is not a noun while conserve is a noun.

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

As verbs, maintain and conserve are synonyms defined as:

maintain and conserve: keep in safety and protect from harm, decay, loss, or destruction

Other synonyms of maintain include keep up, preserve.

As verbs, conserve is a hyponym of maintain; that is, conserve is a word with a more specific, narrower meaning than maintain:

maintain: cause to continue in a certain state, position, or activity
conserve: keep constant through physical or chemical reactions or evolutionary change

maintain (noun)	conserve (noun)
	fruit preserved by cooking with sugar

maintain (verb)	conserve (verb)
stick to correctly or closely	preserve with sugar
state categorically	use cautiously and frugally
state or assert	keep in safety and protect from harm, decay, loss, or destruction
support against an opponent	keep constant through physical or chemical reactions or evolutionary change
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