I've always said I was bloody-minded. Lots of people take that to mean blood-thirsty, which is incorrect. No, it's more of a stubbornness, a willingness to do whatever it takes to accomplish my personal goals. It's not ruthlessness, because that would imply that I'm willing to or even eager to hurt other people, but that's not correct. This doesn't have anything to do with other people.
No, it's the willingness to be ruthless with myself. To ignore my hurts and pains to keep going. Grit might be a better word. Particularly since the dictionary definition of "bloody-minded" seems to be "difficult to deal with : not willing to help others do things." The British define it as someone who is "stubbornly contrary or obstructive." Which are not the meanings I choose.
But grit ... I've certainly gritted my teeth and promised myself that I didn't have to survive another day, another hour, another minute ... just survive another second. And then another. During operations. When I shattered my arm. The cancer scares and the hours and days waiting for test results. The funerals of my mother and then my father -- nightmares that I can never wake up from because they're dead and buried, and that's what life does to us sometimes.
Still, I like my personal definition of bloody-minded best. Sometimes I make words mean what I want them to mean. Don't you?
“When I use a word," Humpty Dumpty said in rather a scornful tone, "it means just what I choose it to mean — neither more nor less."
"The question is," said Alice, "whether you can make words mean so many different things."
"The question is," said Humpty Dumpty, "which is to be master — that’s all.”
― Lewis Carroll, Through the Looking Glass