modesty piece

modesty piece (plural modesty pieces)

1. (now chiefly historical) A piece of lace or other fabric worn over a woman's dress to cover the bosom.
   • July 27, 1711, Leonilla Figleaf, letter to Spectator No. 118

     Now, sir, what I have to communicate to you at present is, that at a late meeting of the stripping ladies, in which were present several eminent toasts and beauties, it was resolved for the future to lay the modesty-piece wholly aside

• modesty bit