stopper

an act so striking or impressive that the show must be delayed until the audience quiets down

a remark to which there is no polite conversational reply

(bridge) a playing card with a value sufficiently high to insure taking a trick in a particular suit; "if my partner has a spade stopper I can bid no trump"

blockage consisting of an object designed to fill a hole tightly

close or secure with or as if with a stopper; "She stoppered the wine bottle"; "The mothers stoppered their babies' mouths with pacifiers"