destiny vs tough luck

destiny and tough luck both are nouns.

Word	Noun	Adjective	Verb	Adverb
destiny	Yes	No	No	No
tough luck	Yes	No	No	No

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

destiny: your overall circumstances or condition in life (including everything that happens to you)
tough luck: an unfortunate state resulting from unfavorable outcomes

Other hyponyms of destiny include good fortune, good luck, luckiness, providence, bad luck, ill luck, misfortune, failure.

destiny (noun)	tough luck (noun)
an event (or a course of events) that will inevitably happen in the future	an unfortunate state resulting from unfavorable outcomes
the ultimate agency regarded as predetermining the course of events
your overall circumstances or condition in life (including everything that happens to you)