Downfall is the collapse or ruin of someone or something that was once powerful, successful, or respected. When a champion athlete's career ends because of injury, or when a once-thriving company goes bankrupt, that's a downfall.

The word suggests a dramatic fall from a high position. A student who stops studying might see their grades plummet from As to Fs, but we usually reserve downfall for more serious situations: a king losing his throne, a leader losing power through scandal, or a great empire crumbling. In Greek mythology, the hero Icarus experienced a literal downfall when he flew too close to the sun with wax wings, causing them to melt and sending him tumbling into the sea.

Often a downfall happens because of a fatal flaw or mistake. Pride led to Napoleon's downfall when he invaded Russia without preparing for winter. Greed can cause the downfall of corrupt politicians. Sometimes people speak of their own downfall: “My love of chocolate will be my downfall” (joking that they can't resist sweets).

The word carries a sense that something once great has been brought low, whether by outside forces, poor choices, or simple bad luck. A downfall is rarely quiet or gentle; it's the moment when everything comes crashing down.