bad luck vs weakness

bad luck and weakness both are nouns.

Word	Noun	Adjective	Verb	Adverb
bad luck	Yes	No	No	No
weakness	Yes	No	No	No

As nouns, weakness is a hyponym of bad luck; that is, weakness is a word with a more specific, narrower meaning than bad luck:

Other hyponyms of bad luck include adversity, hard knocks, hardship, gutter, sewer, toilet, hard cheese.

bad luck (noun)	weakness (noun)
unnecessary and unforeseen trouble resulting from an unfortunate event	the property of lacking physical or mental strength; liability to failure under pressure or stress or strain
an unpredictable outcome that is unfortunate	powerlessness revealed by an inability to act
an unfortunate state resulting from unfavorable outcomes	a penchant for something even though it might not be good for you
	a flaw or weak point
	the condition of being financially weak