Stubbornly adhering to an opinion, purpose, or course, usually with implied unreasonableness; persistent.
(of inanimate things) Not easily subdued or removed.
1925-29, Mahadev Desai (translator), M.K. Gandhi, The Story of My Experiments with Truth, Part IV, Chapter XXIX,
Now it happened that Kasturbai […] had again begun getting haemorrhage, and the malady seemed to be obstinate.
(of a facial feature) Typical of an obstinate person; fixed and unmoving.