stiffness vs resoluteness

stiffness and resoluteness both are nouns.

Word	Noun	Adjective	Verb	Adverb
stiffness	Yes	No	No	No
resoluteness	Yes	No	No	No

As nouns, resoluteness is a hypernym of stiffness; that is, resoluteness is a word with a broader meaning than stiffness:

Other hypernyms of stiffness include firmness, firmness of purpose, resolution, resolve.

stiffness (noun)	resoluteness (noun)
the physical property of being inflexible and hard to bend	the trait of being resolute
the property of moving with pain or difficulty
the inelegance of someone stiff and unrelaxed (as by embarrassment)
excessive sternness
firm resoluteness in purpose or opinion or action