a pernicious and malign influence that is hard to get rid of; "racism is a pestilence at the heart of the nation"; "according to him, I was the canker in their midst"
cool (hot metal) by plunging into cold water or other liquid; "quench steel"
reduce the degree of (luminescence or phosphorescence) in (excited molecules or a material) by adding a suitable substance
satisfy (thirst); "The cold water quenched his thirst"
electronics: suppress (sparking) when the current is cut off in an inductive circuit, or suppress (an oscillation or discharge) in a component or device
put down by force or intimidation; "The government quashes any attempt of an uprising"; "China keeps down her dissidents very efficiently"; "The rich landowners subjugated the peasants working the land"