Source : WordNet®

quieten
     v 1: become quiet or quieter; "The audience fell silent when the
          speaker entered" [syn: {hush}, {quiet}, {quiesce}, {quiet
          down}, {pipe down}] [ant: {louden}]
     2: make calm or still; "quiet the dragons of worry and fear"
        [syn: {calm}, {calm down}, {quiet}, {tranquilize}, {tranquillize},
         {tranquillise}, {lull}, {still}] [ant: {agitate}]
     3: cause to be quiet or not talk; "Please silence the children
        in the church!" [syn: {hush}, {silence}, {still}, {shut up},
         {hush up}] [ant: {louden}]