tragedy has 4 distinct synonyms spread across 1 of its 2 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is comedy.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
an event resulting in great loss and misfortune
“the whole city was affected by the irremediable calamity”
drama in which the protagonist is overcome by some superior force or circumstance; excites terror or pity
Synonyms, antonyms and the broader and narrower relations for tragedy come from Princeton University’s WordNet. Full sources and licences.