hound dog vs hound

hound dog and hound both are nouns.

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

As nouns, hound dog and hound are synonyms defined as:

hound dog and hound: any of several breeds of dog used for hunting typically having large drooping ears

hound dog (noun)	hound (noun)
any of several breeds of dog used for hunting typically having large drooping ears	any of several breeds of dog used for hunting typically having large drooping ears
	someone who is morally reprehensible

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