working man vs employee

working man and employee both are nouns.

Word	Noun	Adjective	Verb	Adverb
working man	Yes	No	No	No
employee	Yes	No	No	No

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

working man (noun)	employee (noun)
an employee who performs manual or industrial labor	a worker who is hired to perform a job