frailness vs frailty

frailness and frailty both are nouns.

Word	Noun	Adjective	Verb	Adverb
frailness	Yes	No	No	No
frailty	Yes	No	No	No

As nouns, frailness and frailty are synonyms defined as:

frailness and frailty: the state of being weak in health or body (especially from old age)

Other synonyms of frailness include debility, feebleness, infirmity, valetudinarianism.

frailness (noun)	frailty (noun)
the state of being weak in health or body (especially from old age)	moral weakness
	the state of being weak in health or body (especially from old age)