flop
1. flop \'fla:p\ vb or flopped; or flop.ping [alter. of 2flap] 1: to swing
or bounce loosely 2: to throw or move oneself in a heavy clumsy, or
relaxed manner 3: to change suddenly 4: to go to bed 5: to fail
completely : to move or drop heavily and noisily - flop.per n
2. flop n 1: an act or sound of flopping 2: a complete failure : DUD
3. flop av : RIGHT, SQUARELY {fell ~ on his face}
Webster's English Dictionary