DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Plop \Plop\ (pl[o^]p), v. i. [imp. & p. p. Plopped (pl[o^]pt);
      p. pr. & vb. n. Plopping.] [Imitative.]
      1. To fall, drop, or move in any way, with a sudden splash or
         slap, as on the surface of water.
         [Webster 1913 Suppl.]
               The body plopped up, turning on its side. --Kipling.
         [Webster 1913 Suppl.]