Something that’s hewn is carved out of wood or another hard material. A hewn rock statue is cut and shaped out of a slab of stone.
Your most prized possession could be a hand-hewn chair made by your grandfather, carved with a chisel out of piece of oak. A child who lives in the country might spend hours with a pocket knife making sharply hewn sticks, one after another. Hewn is the past participle of the verb hew, which comes from the Old English root heawan, “to chop, hack, or gash.”