cowboy vs cowhand

cowboy and cowhand both are nouns.

Word	Noun	Adjective	Verb	Adverb
cowboy	Yes	No	No	No
cowhand	Yes	No	No	No

As nouns, cowhand is a hypernym of cowboy; that is, cowhand is a word with a broader meaning than cowboy:

cowboy: a male hired hand who tends cattle and performs other duties on horseback
cowhand: a hired hand who tends cattle and performs other duties on horseback

Other hypernyms of cowboy include cowherd, cowpoke, cowpuncher, puncher, adult male, man.

cowboy (noun)	cowhand (noun)
someone who is reckless or irresponsible (especially in driving vehicles)	a hired hand who tends cattle and performs other duties on horseback
a performer who gives exhibitions of riding and roping and bulldogging
a male hired hand who tends cattle and performs other duties on horseback