cowpoke vs ranch hand

cowpoke and ranch hand both are nouns.

Word	Noun	Adjective	Verb	Adverb
cowpoke	Yes	No	No	No
ranch hand	Yes	No	No	No

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

cowpoke: a hired hand who tends cattle and performs other duties on horseback
ranch hand: a hired hand on a ranch

cowpoke (noun)	ranch hand (noun)
a hired hand who tends cattle and performs other duties on horseback	a hired hand on a ranch