mid-15c., Peripatetik, "a disciple of Aristotle, one of the set of philosophers who followed the teachings of Aristotle," from Old French perypatetique (14c.) and directly from Medieval Latin peripateticus "pertaining to the disciples or philosophy of Aristotle," from Greek peripatētikos "given to walking about" (especially while teaching), from peripatein "walk up and down, walk about," from peri "around, about" (see peri-) + patein "to walk, tread" (see find (v.)). Aristotle's custom was to teach while strolling through the Lyceum in Athens.
In English, the philosophical meaning is older than that of "person who wanders about" (1610s). As an adjective, "walking about from place to place, itinerant," from 1640s, often with a tinge of humor. Related: Peripatetical.