determined not to change your mind, even when people think you are being unreasonable:
Why are you so stubborn?
I've got a very stubborn streak (=a tendency to be stubborn).
Paul can be as stubborn as a mule (=very stubborn).
a very strong and determined refusal etc:
a stubborn refusal to face reality
difficult to remove, deal with, or use [= tough]:
'I don't care,' she said stubbornly.
—stubbornness noun [uncountable]