Without a heel. Shoes that have a flat sole.(adjective)
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Use "heelless" in a sentence
"They all wore a kind of heelless velvet slipper, very common as a dress shoe in the Philippines, or high-heeled patent leather shoes with neatly fitting black stockings."
"Suddenly the French philosopher Bernard-Henri Lévy wafted in, dressed in black and trailing a cloud of cologne and his mistress, Daphne Guinness, who was wearing a revealing black cat suit and heelless Alexander McQueen platform shoes..."
"In the Zarbia souk men in flowing jalabas hawk carpets, pouffes, babouches the popular heelless leather slippers and brocades."