Quash (verb)

1. To suppress or crush completely.
2. To nullify or make void, especially by legal action.

Origin:

From old french quasser (to break), from vulgar latin quassare, frequentative of latin quatere (to shake).

Examples:

1. The government quashed the rebellion with a brutal crackdown on dissent.
2. The judge quashed the murder conviction due to lack of evidence.
3. The company quashed rumors of a merger by issuing a public statement denying them.
4. The president quashed the proposal to raise taxes on the wealthy.
5. The university quashed the student protest by threatening to expel any participants.