debility vs frailness

debility and frailness both are nouns.

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

As nouns, debility and frailness are synonyms defined as:

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

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

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