obstinate

adjective3

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 […] — 1686
2. •
   Of an inanimate object, not easily subdued or removed.

   • Now it happened that Kasturbai […] had again begun getting haemorrhage, and the malady seemed to be obstinate. — 1925
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. — 1925