Formal:
* Kanaka makua: This literally translates to "adult person" and is a formal way to refer to an adult.
Informal:
* Nui: This word means "big" or "large" and can be used informally to refer to an adult, implying they are older and bigger than a child.
* Kūpuna: This means "elder" or "ancestor" and is used to refer to a person who is wise and respected due to their age.
Other options:
* Kūpaʻa: This means "strong" or "firm" and can be used to describe someone who is mature and responsible.
* Ikaika: This means "strong" or "powerful" and can be used to describe someone who is independent and capable.
The best choice will depend on the specific situation and the desired level of formality.