frailness vs cachexy

frailness and cachexy both are nouns.

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

As nouns, cachexy is a hyponym of frailness; that is, cachexy is a word with a more specific, narrower meaning than frailness:

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

Other hyponyms of frailness include asthenia, astheny, cachexia, wasting, sickliness.

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