obstinate (adj.)

"stubborn in adhering to one's own course, unyielding," late 14c., from Latin obstinatus "resolute, resolved, determined, inflexible, stubborn," past participle of obstinare "persist, stand stubbornly, set one's mind on," from ob "by" (see ob-) + stinare (related to stare "stand"), from PIE *ste-no-, from root *sta- "to stand, make or be firm." Related: Obstinately.