weakness vs penchant

weakness and penchant both are nouns.

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

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

Other hypernyms of weakness include predilection, preference, taste.

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