adverb · quite; rather; very (a colloquial intensifier)

这家店的菜味道蛮正宗的。

adjective · referring to non-Han ethnic groups in ancient southern China or being uncivilized

古代将南方的少数民族称为“蛮”。

adjective, verb · rough; bullying; unreasonable or acting without consideration

你这样蛮干是不行的，得想个好办法。