pum·mel [puhm-uhl]
verb (used with object), pum·meled, pum·mel·ing or ( especially British ) pum·melled, pum·mel·ling.
to beat or thrash with or as if with the fists.

I always thought that there was also a word PUMBLE that meant the same thing as PUMMEL.

Obviously I was wrong.

It was always used when we were playing sport and we would say that, "we pumbled the opposition."

Urban Dictionary has not let me down, it does exist.

They have chimbley, too.

Urban Dictionary may not always be a reliable source.

But if you read the UD entry, you might note that it does imply that pumble is a corruption of pummel.

You can only take each entry on it's own merits.