na-adjective, noun
obstinate; stubborn; headstrong
Describes a person who refuses to change their opinion or behavior, often with a negative connotation of inflexibility.
彼は強情だから、一度言い出したら聞かない。
He's stubborn, so once he says something, he won't listen.
あの子は強情で、謝ろうとしない。
That child is obstinate and refuses to apologize.