His bullheadedness prevented the treatment plan from moving forward despite the doctor's professional advice.

bullheadedness 是由形容词 bullheaded 加上名词后缀 -ness 构成的名词。bullheaded 由 bull（公牛）和 headed（有...头的）组成，字面意思是"像公牛一样顽固的"，比喻"固执的、倔强的"。 bullheadedness 指"固执、倔强的性格或态度"。