v. t. [ 1st pref. un- + step. ] (Naut.) To remove, as a mast, from its step. [ 1913 Webster ]
n. [ Formerly also instop, instup. ] [ 1913 Webster ]
1. The arched middle portion of the human foot next in front of the ankle joint. [ 1913 Webster ]
2. The part of a shoe, boot, or stocking covering the instep{ 1 }. [ PJC ]
3. That part of the hind leg of the horse and allied animals, between the hock, or ham, and the pastern joint. [ 1913 Webster ]