To fall, drop, or move in any way, with a sudden splash or slap, as on the surface of water.
- To fall with a sound like that of an object falling into water without splashing.
- To let the body drop heavily: Exhausted, I plopped into the armchair.
- To drop or set heavily, with or as if with a plopping sound: plopped the child into the stroller.
- A plopping sound or movement.