Harry had expected Ron to be stunned by Malfoys boasts. With what Harry considered pure pigheadedness, however, Ron was unimpressed.

哈利本来以为罗恩听了马尔福那些吹牛的话会感到很震惊。可是罗恩竟然觉得无动于衷，哈利觉得他简直是变成榆木脑袋了。

So, " pigheadedness" is the state of or the condition of being stubborn.

所以，“pigheadedness”是固执的状态或状态。

Well, there's strong and there's pigheadedness.

德克：嗯，有坚强也有固执。