Obstinate means refusing to change your mind, whatever anybody says. Dug in, and enjoying it slightly.
It is nearly always a criticism, which is what separates it from determined, since the same behaviour is determination when you agree and obstinacy when you do not. It also describes things, and an obstinate stain or an obstinate lid refuses to give way. Medicine uses obstinate for a condition that will not respond to treatment. The noun is obstinacy, and stubborn is the everyday equivalent.
1adjectiveobstinateRefusing to change an opinion or course of action.
“He was obstinate about not seeing a doctor.”
2adjectivedifficultDifficult to remove or overcome.
“There was an obstinate mark on the carpet.”
Too few real examples of this word to estimate which sense is commonest.
Also accepted in games: stubborn
Obstinate is standing in the way. Latin obstinō joins ob, before, to stāre, to stand, so to be obstinate is to plant yourself in front of a thing and decline to move.
Proto-Indo-European
*steh₂-
Latin
obstinātus
Middle English
obstinat — obstinate, stubborn
English, today
obstinate
Built from
Middle English obstinat (“obstinate, stubborn”), from Latin obstinātus, perfect passive participle of obstinō (“set one's mind firmly upon, resolve”) (see -ate), from ob (“before”) + *stinare, from stare (“to stand”). a doublet of ostinato.
Etymology from Wiktionary, CC BY-SA