stubborn

Refusing to move or to change one's opinion; obstinate; firmly resisting; persistent in doing something.

People are pretty stubborn about their political beliefs, so why bother arguing?

Blood can make a very stubborn stain on fabrics if not washed properly.

Of materials: physically stiff and inflexible; not easily melted or worked.

Stubbornness.

But I have to say that one thing you inherited from your mother is a whole lot of stubborn.

That takes a lot of stubborn for a seventy-something man.

Ellipsis of stubborn disease (“a disease of citrus trees”).

With evidence that the causal agent of stubborn is spread by insects, control or prevention of this disease will prove more difficult than formerly thought to be.

Sectorial infection of stubborn could be stable for long periods, but may be manifested once the trees are severely pruned, this causing the system spread of S. citri to other non-infected parts.