pye-dog vs mongrel

pye-dog and mongrel both are nouns.

Word	Noun	Adjective	Verb	Adverb
pye-dog	Yes	No	No	No
mongrel	Yes	No	No	No

As nouns, mongrel is a hypernym of pye-dog; that is, mongrel is a word with a broader meaning than pye-dog:

pye-dog: ownerless half-wild mongrel dog common around Asian villages especially India
mongrel: an inferior dog or one of mixed breed

Other hypernyms of pye-dog include cur, mutt.

pye-dog (noun)	mongrel (noun)
ownerless half-wild mongrel dog common around Asian villages especially India	an inferior dog or one of mixed breed
	derogatory term for a variation that is not genuine; something irregular or inferior or of dubious origin