obstinacy vs bullheadedness

obstinacy and bullheadedness both are nouns.

Word	Noun	Adjective	Verb	Adverb
obstinacy	Yes	No	No	No
bullheadedness	Yes	No	No	No

As nouns, obstinacy and bullheadedness are synonyms defined as:

obstinacy and bullheadedness: resolute adherence to your own ideas or desires

Other synonyms of obstinacy include obstinance, pigheadedness, self-will, stubbornness.

obstinacy (noun)	bullheadedness (noun)
the trait of being difficult to handle or overcome	resolute adherence to your own ideas or desires
resolute adherence to your own ideas or desires