WordNet (r) 3.0 (2006):

grand mal
    n 1: epilepsy in which the attacks involve loss of consciousness
         and tonic spasms of the musculature followed by generalized
         jerking [syn: grand mal epilepsy, grand mal,
         generalized epilepsy, epilepsia major]
    2: a seizure during which the patient becomes unconscious and
       has convulsions over the entire body [syn: grand mal,
       generalized seizure, epilepsia major]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "grand mal":
   Jacksonian epilepsy, Rolandic epilepsy, abdominal epilepsy, access,
   acquired epilepsy, activated epilepsy, affect epilepsy,
   akinetic epilepsy, apoplexy, arrest, attack, autonomic epilepsy,
   blockage, cardiac epilepsy, clonic spasm, clonus, convulsion,
   cortical epilepsy, cramp, cursive epilepsy, diurnal epilepsy,
   eclampsia, epilepsia, epilepsia gravior, epilepsia major,
   epilepsia minor, epilepsia mitior, epilepsia nutans,
   epilepsia tarda, epilepsy, falling sickness, fit, focal epilepsy,
   frenzy, haute mal, hysterical epilepsy, ictus, larval epilepsy,
   laryngeal epilepsy, laryngospasm, latent epilepsy, lockjaw,
   matutinal epilepsy, menstrual epilepsy, musicogenic epilepsy,
   myoclonous epilepsy, nocturnal epilepsy, occlusion, paroxysm,
   petit mal, physiologic epilepsy, psychic epilepsy,
   psychomotor epilepsy, reflex epilepsy, rotatoria, seizure,
   sensory epilepsy, serial epilepsy, spasm, stoppage, stroke,
   tardy epilepsy, tetanus, tetany, throes, thromboembolism,
   thrombosis, tonic epilepsy, tonic spasm, torsion spasm,
   traumatic epilepsy, trismus, ucinate epilepsy, visitation