cachexia vs infirmity

cachexia and infirmity both are nouns.

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

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

cachexia: 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 cachexia include debility, feebleness, frailness, frailty, valetudinarianism.

cachexia (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)