cataclysmic

from WordNet (r) 3.0 (2006)

cataclysmic
    adj 1: severely destructive; "cataclysmic nuclear war"; "a
           cataclysmic earthquake" [syn: {cataclysmal},
           {cataclysmic}]

from The Collaborative International Dictionary of English v.0.48

Cataclysmal \Cat`a*clys"mal\, Cataclysmic \Cat`a*clys"mic\, a.
   Of or pertaining to a cataclysm.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

57 Moby Thesaurus words for "cataclysmic":
      baneful, black, calamitous, cataclysmal, catastrophic, consuming,
      consumptive, convulsive, deadly, demolishing, demolitionary,
      depredatory, desolating, destroying, destructive, devastating,
      dire, disastrous, doomful, fatal, fateful, fratricidal, grievous,
      herky-jerky, insurrectionary, internecine, jerky, nihilist,
      nihilistic, orgasmic, paroxysmal, radical, ravaging, revolutional,
      revolutionary, revulsionary, revulsive, ruining, ruinous, seismic,
      self-destructive, spasmodic, spastic, subversionary, subversive,
      suicidal, sweeping, tragic, transilient, upheaving, vandalic,
      vandalish, vandalistic, wasteful, wasting, withering, wreckful