feebleness vs wasting

feebleness and wasting both are nouns.

Word	Noun	Adjective	Verb	Adverb
feebleness	Yes	No	No	No
wasting	Yes	No	No	No

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

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

Other hyponyms of feebleness include asthenia, astheny, cachexia, cachexy, sickliness.

feebleness (noun)	wasting (noun)
the quality of lacking intensity or substance	a decrease in size of an organ caused by disease or disuse
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