Definition of slop about

The expression "slop about" derives from the nautical term "slop" which century-old sailors used to describe their clothing or uniforms. These clothes were often ill-fitting and becoming baggy and worn due to constant use and exposure to the elements. The term "slop" was also used to refer to food that was served to sailors as an emergency ration when supplies ran low. This food was simple and lacked the nutritional value needed to sustain the sailors through long periods at sea. The expression "slop about" then, can be understood as referring to the motion of someone who is moved about by the motion of a ship, tossing their bulk around like spilled food or ill-fitting clothing. The phrase originated in this context in naval terminology and became a word commonly used descriptively for those who move clumsily or with no apparent purpose in everyday life.