mulishly vs pig-headedly

mulishly and pig-headedly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
mulishly	No	No	No	Yes
pig-headedly	No	No	No	Yes

As adverbs, mulishly and pig-headedly are synonyms defined as:

Other synonyms of mulishly include cussedly, obdurately, obstinately, stubbornly.

mulishly (adverb)	pig-headedly (adverb)
in a stubborn unregenerate manner	in a stubborn unregenerate manner