dairyman vs field hand

dairyman and field hand both are nouns.

Word	Noun	Adjective	Verb	Adverb
dairyman	Yes	No	No	No
field hand	Yes	No	No	No

As nouns, field hand is a hypernym of dairyman; that is, field hand is a word with a broader meaning than dairyman:

Other hypernyms of dairyman include farm worker, farmhand, fieldhand.

dairyman (noun)	field hand (noun)
the owner or manager of a dairy	a hired hand on a farm
a man who works in a dairy