mid-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" (see stet). Related: Obstinately.