herder vs sheepherder

herder and sheepherder both are nouns.

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

As nouns, sheepherder is a hyponym of herder; that is, sheepherder is a word with a more specific, narrower meaning than herder:

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

Other hyponyms of herder include goat herder, goatherd, sheepman, shepherd, pigman, swineherd.

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