stopper in WordNet English dictionary

1. a remark to which there is no polite conversational reply
   conversation stopper  stopper 
   
2. blockage consisting of an object designed to fill a hole tightly
   plug  stopper  stopple 
   
3. an act so striking or impressive that the show must be delayed until the audience quiets down
   show-stopper  showstopper  stopper 
   
4. (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"
   stopper 
   

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