roper vs cowpuncher

roper and cowpuncher both are nouns.

Word	Noun	Adjective	Verb	Adverb
roper	Yes	No	No	No
cowpuncher	Yes	No	No	No

As nouns, cowpuncher is a hypernym of roper; that is, cowpuncher is a word with a broader meaning than roper:

roper: a cowboy who uses a lasso to rope cattle or horses
cowpuncher: a hired hand who tends cattle and performs other duties on horseback

Other hypernyms of roper include cowhand, cowherd, cowpoke, puncher.

roper (noun)	cowpuncher (noun)
a craftsman who makes ropes	a hired hand who tends cattle and performs other duties on horseback
a cowboy who uses a lasso to rope cattle or horses
a decoy who lures customers into a gambling establishment (especially one with a fixed game)