Pathology. a condition characterized by sudden, brief attacks of muscle weakness sometimes causing the body to fall helplessly, that is usually triggered by strong emotion: often associated with narcolepsy.
1880-85; < GermanKataplexie < Greekkatáplēxis (with suffix probably by analogy with Apoplexieapoplexy) fixation (of the eyes), equivalent to kataplēk- (variant stem of kataplḗssein to strike down) + -sis-sis
"the state of an animal when it is feigning death," 1883, from Ger. kataplexie, from Gk. kataplexis "stupefaction," from kataplessein "to strike down" (with fear, etc.), from kata- "down" + plessein "to strike, hit."