black eye vs whammy

black eye and whammy both are nouns.

Word	Noun	Adjective	Verb	Adverb
black eye	Yes	No	No	No
whammy	Yes	No	No	No

As nouns, whammy is a hyponym of black eye; that is, whammy is a word with a more specific, narrower meaning than black eye:

black eye: an unfortunate happening that hinders or impedes; something that is thwarting or frustrating
whammy: a serious or devastating setback

black eye (noun)	whammy (noun)
an unfortunate happening that hinders or impedes; something that is thwarting or frustrating	an evil spell
a swollen bruise caused by a blow to the eye	a serious or devastating setback
a bad reputation