maintenance man vs fixer

maintenance man and fixer both are nouns.

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

As nouns, fixer is a hypernym of maintenance man; that is, fixer is a word with a broader meaning than maintenance man:

Other hypernyms of maintenance man include mender, repairer.

maintenance man (noun)	fixer (noun)
a skilled worker whose job is to repair things	synthetic narcotic drug similar to morphine but less habit-forming; used in narcotic detoxification and maintenance of heroin addiction
	someone who intervenes with authorities for a person in trouble (usually using underhand or illegal methods for a fee)
	a skilled worker who mends or repairs things
	a chemical compound that sets or fixes something (as a dye or a photographic image)