If you needed to cover you head with a hood, you'd probably hope it was made of material sturdy — or hardy — enough to keep you warm in the winter wind. Hardihood, however, isn't something you can layer on the outside of your body. The hardihood that would help you survive discomfort or disaster would be the strength of your spirit — your courage or boldness in the face of something difficult or dramatic.
From Charlotte Brontë's Victorian novel, Jane Eyre:
I hardly know where I found the hardihood thus to open a conversation with a stranger; the step was contrary to my nature and habits: but I think her occupation touched a chord of sympathy somewhere; for I too liked reading, though of a frivolous and childish kind; I could not digest or comprehend the serious or substantial.