inadequacy vs weakness

inadequacy and weakness both are nouns.

Word	Noun	Adjective	Verb	Adverb
inadequacy	Yes	No	No	No
weakness	Yes	No	No	No

As nouns, weakness is a hypernym of inadequacy; that is, weakness is a word with a broader meaning than inadequacy:

Other hypernyms of inadequacy include failing.

inadequacy (noun)	weakness (noun)
unsatisfactoriness by virtue of being inadequate	the property of lacking physical or mental strength; liability to failure under pressure or stress or strain
lack of an adequate quantity or number	powerlessness revealed by an inability to act
a lack of competence	a penchant for something even though it might not be good for you
	a flaw or weak point
	the condition of being financially weak