stiffness vs awkwardness

stiffness and awkwardness both are nouns.

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

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

stiffness: the property of moving with pain or difficulty
awkwardness: the carriage of someone whose movements and posture are ungainly or inelegant

Other hypernyms of stiffness include clumsiness.

As nouns, stiffness and awkwardness are synonyms defined as:

stiffness and awkwardness: the inelegance of someone stiff and unrelaxed (as by embarrassment)

Other synonyms of stiffness include clumsiness, gracelessness.

stiffness (noun)	awkwardness (noun)
the physical property of being inflexible and hard to bend	the carriage of someone whose movements and posture are ungainly or inelegant
the property of moving with pain or difficulty	the quality of an embarrassing situation
the inelegance of someone stiff and unrelaxed (as by embarrassment)	trouble in carrying or managing caused by bulk or shape
excessive sternness	the inelegance of someone stiff and unrelaxed (as by embarrassment)
firm resoluteness in purpose or opinion or action	unskillfulness resulting from a lack of training