odd-job man vs maintenance man

odd-job man and maintenance man both are nouns.

Word	Noun	Adjective	Verb	Adverb
odd-job man	Yes	No	No	No
maintenance man	Yes	No	No	No

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

Other hypernyms of odd-job man include repairman, service man.

odd-job man (noun)	maintenance man (noun)
a man skilled in various odd jobs and other small tasks	a skilled worker whose job is to repair things