尽管医生建议他戒烟，但他的固执让他继续每天抽两包烟。

Despite the doctor's advice to quit smoking, his obstinacy made him continue smoking two packs a day.

obstinacy 是名词，来自形容词 obstinate（固执的），后缀 -acy 表示性质或状态。obstinacy 指"固执、顽固"的性格特征或行为表现。