late 14c., "sudden fit of paralysis and dizziness," from Old French apoplexie or directly from Late Latin apoplexia, from Greek apoplexia, from apoplessein "to strike down and incapacitate," from apo- "off" (see apo-), in this case probably an intensive prefix, + plessein "hit" (cf. plague (n.), also with a root sense of "stricken"). The Latin translation, sideratio, means "disease caused by a constellation."
apoplexy ap·o·plex·y (āp'ə-plěk'sē)
Sudden impairment of neurological function, especially from a cerebral hemorrhage; a stroke.
An effusion of blood into a tissue or organ.