stiffness vs inelegance

stiffness and inelegance both are nouns.

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

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

stiffness: the inelegance of someone stiff and unrelaxed (as by embarrassment)
inelegance: the quality of lacking refinement and good taste

stiffness (noun)	inelegance (noun)
the physical property of being inflexible and hard to bend	the quality of lacking refinement and good taste
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