frailty vs infirmity

frailty and infirmity both are nouns.

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

As nouns, frailty and infirmity are synonyms defined as:

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

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

frailty (noun)	infirmity (noun)
moral weakness	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)