Of footwear, having very low heels so that the foot is almost parallel to the ground; low-heeled.
1938, Norman Lindsay, Age of Consent, 1st Australian edition, Sydney, N.S.W.: Ure Smith, published 1962, →OCLC, page 128:
Recovered from reverie, Miss Marley joined him, coming cautiously over the rocks in her flat-heeled shoes, and skimping back her frock a little to mark her step.