ischemic stroke vs apoplexy

ischemic stroke and apoplexy both are nouns.

Word	Noun	Adjective	Verb	Adverb
ischemic stroke	Yes	No	No	No
apoplexy	Yes	No	No	No

As nouns, apoplexy is a hypernym of ischemic stroke; that is, apoplexy is a word with a broader meaning than ischemic stroke:

ischemic stroke: the most common kind of stroke; caused by an interruption in the flow of blood to the brain (as from a clot blocking a blood vessel)
apoplexy: a sudden loss of consciousness resulting when the rupture or occlusion of a blood vessel leads to oxygen lack in the brain

Other hypernyms of ischemic stroke include cerebrovascular accident, CVA, stroke, ischaemia, ischemia.

ischemic stroke (noun)	apoplexy (noun)
the most common kind of stroke; caused by an interruption in the flow of blood to the brain (as from a clot blocking a blood vessel)	a sudden loss of consciousness resulting when the rupture or occlusion of a blood vessel leads to oxygen lack in the brain