1. one's own legs, esp. as a means of moving from one place to another: The only way we can get there is by shanks' mare.
2. ride shanks' mare, to go on foot rather than ride; walk: It was such a delightful day that we decided to ride shanks' mare to the fair. Also,shank's' mare'.Also called shanks'' po'ny, shank's' po'ny.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.