sling-back

[sling-bak]
noun
  1. Also called sling. a woman's shoe with an open back and a strap or sling encircling the heel of the foot to keep the shoe secure.
adjective
  1. having such a strap or sling: sling-back pumps.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for slingback

slingback

noun
    1. a shoe with a strap instead of a full covering for the heel
    2. (as modifier)slingback shoes
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012