slop

cause or allow (a liquid substance) to run or flow from a container

spill the milk

wet feed (especially for pigs) consisting of mostly kitchen waste mixed with water or skimmed or sour milk

walk through mud or mire

We had to splosh across the wet meadow

deep soft mud in water or slush

they waded through the slop

(usually plural) waste water from a kitchen or bathroom or chamber pot that has to be emptied by hand

she carried out the sink slops