quench verb [T]. › to ​drink ​liquid so that you ​stop being ​thirsty: When it's ​hot, it's ​best to quench ​your ​thirst with ​water. › literary to use ​water to put out a ​fire: The ​flames were quenched by ​heavy ​rain. › to ​satisfy a need or ​wish: Her ​thirst for ​knowledge will never be quenched.