cachexy vs infirmity

cachexy and infirmity both are nouns.

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

As nouns, infirmity is a hypernym of cachexy; that is, infirmity is a word with a broader meaning than cachexy:

cachexy: any general reduction in vitality and strength of body and mind resulting from a debilitating chronic disease
infirmity: the state of being weak in health or body (especially from old age)

Other hypernyms of cachexy include debility, feebleness, frailness, frailty, valetudinarianism.

cachexy (noun)	infirmity (noun)
any general reduction in vitality and strength of body and mind resulting from a debilitating chronic disease	the state of being weak in health or body (especially from old age)