stubborn
adj.adj. refusing to change your mind or your behavior, even when other people have good reasons for you to do so. It is often used to describe someone who is difficult to work with.
adj. unreasonably or perversely unyielding; refusing to move or change one's opinion despite persuasion or argument. Often carries a negative connotation of inflexibility, though it can occasionally imply persistence.
He is too stubborn to admit he is wrong.
The stubborn child refused to eat his vegetables despite his parents promising him dessert afterward.
The negotiations stalled because both parties remained stubborn regarding the final price, refusing to make even the slightest concession to reach a middle ground.
From Middle English stiborne, stibourne, stoburn, stoburne, styburne, stiborn, of uncertain origin; one hypothesis is that it may be from Old English *stybbor, from Old English stybb (“a stump, stub”) + -or (adjective-formation suffix, as in bitor, whence English bitter).
Typically used as an attributive adjective before a noun or a predicative adjective after a linking verb like 'be' or 'seem'.