obstinate

adj

1. Stubbornly adhering to an opinion, purpose, or course, usually with implied unreasonableness; persistent.

   “From this consideration it is that we have derived the custom, in times of war, to punish […] those who are obstinate to defend a place that by the rules of war is not tenable […]”

   “[…] the junior Osborne was quite as obstinate as the senior: when he wanted a thing, quite as firm in his resolution to get it; and quite as violent when angered, as his father in his most stern moments”

2. Of an inanimate object, not easily subdued or removed.

   “an obstinate blockage in the pipe”

   “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.”

3. Of a facial feature or expression, fixed and unmoving.

   “He had the same pile of curly hair, but he was clean-shaven with a heavy, obstinate jowl.”