rustiness vs awkwardness

rustiness and awkwardness both are nouns.

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

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

rustiness: ineptitude or awkwardness as a consequence of age or lack of practice
awkwardness: unskillfulness resulting from a lack of training

Other hypernyms of rustiness include clumsiness, ineptitude, ineptness, maladroitness, slowness.

rustiness (noun)	awkwardness (noun)
ineptitude or awkwardness as a consequence of age or lack of practice	the carriage of someone whose movements and posture are ungainly or inelegant
the condition of being coated or clogged with rust	the quality of an embarrassing situation
	trouble in carrying or managing caused by bulk or shape
	the inelegance of someone stiff and unrelaxed (as by embarrassment)
	unskillfulness resulting from a lack of training