Definitions of stopper:

• noun:   (bridge) a playing card with a value sufficiently high to insure taking a trick in a particular suit

  Example: "If my partner has a spade stopper I can bid no trump"

• noun:   blockage consisting of an object designed to fill a hole tightly
• noun:   a remark to which there is no polite conversational reply
• noun:   an act so striking or impressive that the show must be delayed until the audience quiets down
• verb:   close or secure with or as if with a stopper

  Example: "She stoppered the wine bottle"