bad luck vs hard cheese

bad luck and hard cheese both are nouns.

Word	Noun	Adjective	Verb	Adverb
bad luck	Yes	No	No	No
hard cheese	Yes	No	No	No

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

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

bad luck (noun)	hard cheese (noun)
unnecessary and unforeseen trouble resulting from an unfortunate event	bad luck
an unpredictable outcome that is unfortunate
an unfortunate state resulting from unfavorable outcomes