Definition of stubborn:

part of speech: adjective

Unbending, like a stub; rigid; obstinate; inflexibly headstrong.

Usage examples:

• He was still stubborn Dallas McCord Reynolds in "Frigid Fracas".

• He might be less stubborn Grace Livingston Hill Lutz in "Marcia Schuyler".

• Maximilian knew how stubborn she could be; and so, reluctantly, he joined the plot. Eugene P. (Eugene Percy) Lyle in "The Missourian".