herdsman vs sheepman

herdsman and sheepman both are nouns.

Word	Noun	Adjective	Verb	Adverb
herdsman	Yes	No	No	No
sheepman	Yes	No	No	No

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

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

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

herdsman (noun)	sheepman (noun)
someone who drives a herd	a man who raises (or tends) sheep
	a herder of sheep (on an open range); someone who keeps the sheep together in a flock