piepowder (n.)

early 13c., pe-poudre, "wayfarer, itinerant merchant, etc.," folk etymology alteration of Old French pie pouldre or Medieval Latin pede-pulverosus, both literally "dusty-footed." The first element is from Latin pedem "foot" (from PIE root *ped- "foot"); for second element see powder (n.)). Often in reference to an old court of record in England held at fairs and markets.