cataclysm

1 a great flow of water or of something that overwhelms an ancient cataclysm that may have been the basis for the Flood described in the Bible Synonyms alluvion, bath, flood, cataract, deluge, flood tide, inundation, Niagara, overflow, spate, torrentRelated Words current, river, stream, tide; cloudburst, discharge, flush, gush, outflow, outpouring; flux, inflow, influx; engulfment, washout; avalanche, blizzard; cascade, waterfall; excess, glut, overabundance, overage, overkill, overmuch, oversupply, superabundance, superfluity, surfeit, surplusNear Antonyms dribble, drip, trickleAntonyms drought (also drouth)

2 a sudden violent event that brings about great loss or destruction the earthquake that struck Lisbon in 1755, killing 30,000 people, was one of the greatest cataclysms ever recorded Synonyms apocalypse, calamity, disaster, catastrophe, debacle (also débâcle), tragedyRelated Words bloodbath, collapse, crash, meltdown; Armageddon, doomsday, end-time; convulsion, paroxysm, upheaval; accident, casualty, fatality; misadventure, mischance, misfortune, mishap; blast, blow, double whammy, one-two (or one-two punch)Near Antonyms godsend, manna, windfall

3 a violent disturbance (as of the political or social order) a social cataclysm that gave rise to a new world order Synonyms bouleversement, convulsion, earthquake, paroxysm, storm, tempest, tumult, upheaval, uproarRelated Words insurgency, insurrection, mutiny, overthrow, overturn, rebellion, revolt, revolution, subversion, unrest, uprising, upset; fit, seizure, spasm; eruption, flare-up, outbreak, outburst; bluster, bobbery, bustle, coil, commotion, furor, furore, fuss, hubbub, hullabaloo, hurly-burly, pandemonium, rout, row, ruckus, ruction, rumpus, shindy, squall, stew, stir, to-do, turmoil, welter, williwaw; quaking, rocking, shaking, trembling