General stubbornness:
* Paʻakikī: This word means "hard, difficult, stubborn." It conveys the idea of being inflexible and resistant to change.
* ʻAʻole hoʻolohe: This literally translates to "not listening." It suggests a refusal to consider other perspectives.
* Kūpaʻa: This word means "firm, steadfast, unwavering." It could be used to describe someone who is resolute in their own opinions.
Specifically headstrong:
* Poʻo paʻakikī: This literally means "hard-headed," but is not a common phrase. It might sound a bit more literal and less idiomatic than other options.
Negative connotation:
* Nānā ʻole: This means "careless, inconsiderate." It implies that the person is being stubborn and not considering the consequences of their actions.
Ultimately, the best word to use will depend on the specific context and what nuance you want to convey.