Ruination
Part of speech: noun
Definition: The state of being ruined, a state of devastation or destruction. The act of ruining or wrecking. The cause of being ruined, destroyed or lost. A loss of reputation.
Downfall
Part of speech: noun
Definition: A precipitous decline in fortune; a rapid deterioration, as in status or wealth.The cause of such a fall; a critical blow or error.
Example sentence: The downfall of any leader in a sport's team is when he gets carried away with his own ego.