DEFEATS

To overcome in battle or contest.

"Wellington defeated Napoleon at Waterloo."

To reduce, to nothing, the strength of.

To nullify

The act or instance of being defeated, of being overcome or vanquished; a loss.

"Licking their wounds after a temporary defeat, they planned their next move."

The act or instance of defeating, of overcoming, vanquishing.

"The inscription records her defeat of the country's enemies in a costly war."

Frustration (by prevention of success), stymieing; nullification.