Shank's pony is an idiomatic expression that refers to walking on foot. It is commonly used in British English, but there are many other phrases that have the same meaning. Some synonyms for shank's pony include on foot, by foot, walking, hiking, trekking, tramping, and strolling. These phrases can be used interchangeably depending on the context of the sentence. For instance, if someone asks how you plan to get to your destination, you could say that you're going to use shank's pony or simply say that you plan on walking there. Regardless of the phrase you use, they all imply the same thing - traveling by foot.