sheepherder vs drover

sheepherder and drover both are nouns.

Word	Noun	Adjective	Verb	Adverb
sheepherder	Yes	No	No	No
drover	Yes	No	No	No

As nouns, drover is a hypernym of sheepherder; that is, drover is a word with a broader meaning than sheepherder:

sheepherder: a herder of sheep (on an open range); someone who keeps the sheep together in a flock
drover: someone who drives a herd

Other hypernyms of sheepherder include herder, herdsman.

sheepherder (noun)	drover (noun)
a herder of sheep (on an open range); someone who keeps the sheep together in a flock	someone who drives a herd