Shlepper is a slang term for someone who carries or hauls things around. It can also mean someone who is lazy or inefficient. There are various synonyms for this word, depending on the context in which it is used. If the meaning is closer to "lazy," then sluggish, indolent, or lethargic could be suitable alternatives. If the meaning is more like "transporter," synonyms like hauler, carrier, or transporter could be more appropriate. Other words that could be interchangeable for shlepper could include schlepper, dragger, or lugger. Ultimately, the synonym used for shlepper would depend on the context in which the word is being used.