1. sequel A cataclysm or catastrophe is some great convulsion or momentous event that may or may not be a cause of misery to man. In calamity, or disaster, the thought of human suffering is always pres Synonyms: catastrophe, calamity, denouement, mischance, mishap, cataclysm, disaster, misfortune, sequel Antonyms: benefit, boon, favor, pleasure, prosperity, blessing, comfort, help, privilege, success