maintenance man vs service man

maintenance man and service man both are nouns.

Word	Noun	Adjective	Verb	Adverb
maintenance man	Yes	No	No	No
service man	Yes	No	No	No

As nouns, maintenance man and service man are synonyms defined as:

maintenance man and service man: a skilled worker whose job is to repair things

Other synonyms of maintenance man include repairman.

maintenance man (noun)	service man (noun)
a skilled worker whose job is to repair things	a skilled worker whose job is to repair things