feebleness vs astheny

feebleness and astheny both are nouns.

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

As nouns, astheny is a hyponym of feebleness; that is, astheny 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)
astheny: an abnormal loss of strength

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

feebleness (noun)	astheny (noun)
the quality of lacking intensity or substance	an abnormal loss of strength
the state of being weak in health or body (especially from old age)