pug-dog vs pug

pug-dog and pug both are nouns.

Word	Noun	Adjective	Verb	Adverb
pug-dog	Yes	No	No	No
pug	Yes	No	No	No

As nouns, pug-dog and pug are synonyms defined as:

pug-dog and pug: small compact smooth-coated breed of Asiatic origin having a tightly curled tail and broad flat wrinkled muzzle

pug-dog (noun)	pug (noun)
small compact smooth-coated breed of Asiatic origin having a tightly curled tail and broad flat wrinkled muzzle	small compact smooth-coated breed of Asiatic origin having a tightly curled tail and broad flat wrinkled muzzle