"sudden fit of paralysis and dizziness," late 14c., from Old French apoplexie or directly from Late Latin apoplexia, from Greek apoplexia, from apoplektos "disabled by a stroke, struck dumb," verbal adjective from apoplessein "to strike down and incapacitate," from apo "off" (see apo-), in this case probably an intensive prefix, + plessein "to hit," from PIE root *plak- (2) "to strike" (source also of plague, which also has a root sense of "stricken"). The Latin translation, sideratio, means "disease caused by a constellation."
