To splosh is to move with a splashing sound or motion. You might splosh through a marsh to retrieve your escaped canoe.
You can splosh through the surf as you wait for a good body surfing wave, or you can splosh a pan of soapy water into your sink. Before most of us learn to swim, we mainly splosh through the water, keeping our feet touching the bottom of the pool. The word splosh sounds just like its meaning — its origin is imitative, very similar to splash. Both words were first used in the mid-nineteenth century.