Unpersuadable

I wish, for both our sakes, my dear unpersuadable girl, that the decision of this point lay with me. But why, when you know it does not, why should you thus perplex and urge me?

He was unreasonable and unpersuadable and used intemperate language.

For not by prayer to Zeus is access won; An unpersuadable heart hath Cronos' son.

He did not boast, but it naturally betrayed itself, that he had persuaded his aunt where his uncle could do nothing, and on her laughing and noticing it, he owned that he believed (excepting one or two points) he could with time persuade her to any thing. […] The unpersuadable point, which he did not mention, Emma guessed to be good behaviour to his father.

Compared with the researchers’ own anxious exertions and the towering unknowns that swirled before them, Boger’s calm and assiduous attention to his slides seemed to many of them—dangerously, a few argued—aloof. ¶ Boger thought to convince them otherwise was “an unpersuadable issue,” and so he didn’t try.