doomsday
doom-sday
noun
The final day of the world's existence; a time of ultimate destruction.
"Many fear a doomsday scenario for the planet."
Thesaurus
Synonyms: Last Judgement, Day of Judgement, Last Judgment, Last Day, day of reckoning, Judgment Day, Day of Judgment, eschaton, end of the world, Judgement Day, crack of doom, doom