pie-dog vs mutt

pie-dog and mutt both are nouns.

Word	Noun	Adjective	Verb	Adverb
pie-dog	Yes	No	No	No
mutt	Yes	No	No	No

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

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

Other hypernyms of pie-dog include cur, mongrel.

pie-dog (noun)	mutt (noun)
ownerless half-wild mongrel dog common around Asian villages especially India	an inferior dog or one of mixed breed