greyhound vs hound

greyhound and hound both are nouns.

Word	Noun	Adjective	Verb	Adverb
greyhound	Yes	No	No	No
hound	Yes	No	Yes	No

As nouns, hound is a hypernym of greyhound; that is, hound is a word with a broader meaning than greyhound:

greyhound: a tall slender dog of an ancient breed noted for swiftness and keen sight; used as a racing dog
hound: any of several breeds of dog used for hunting typically having large drooping ears

Other hypernyms of greyhound include hound dog, racer.

greyhound (noun)	hound (noun)
a tall slender dog of an ancient breed noted for swiftness and keen sight; used as a racing dog	any of several breeds of dog used for hunting typically having large drooping ears
	someone who is morally reprehensible

greyhound (verb)	hound (verb)
	pursue or chase relentlessly