c.1400, n., "disciple of Aristotle," from O.Fr. perypatetique (14c.), from L. peripateticus "pertaining to the disciples or philosophy of Aristotle," from Gk. peripatetikos "given to walking about" (especially while teaching), from peripatein, from peri- "around" + patein "to walk." Aristotle's custom was to teach while strolling through the Lyceum in Athens. In Eng., the philosophical meaning is older than that of "person who wanders about" (1617). As an adj., attested in Eng. 1566 in the philosophical sense, 1642 in the lit. sense.
"itinerant entertainer," 1857, from busk (v.) "to offer goods for sale only in bars and taprooms," 1851 (in Mayhew), probably from busk "to cruise as a pirate," which was used in a fig. sense by 1841, in ref. to people living shifless and peripatetic lives. The nautical term is attested from 1665 (in a general sense of "to tack, to beat to windward"), apparently from obs. Fr. busquer "to shift, filch, prowl," which is related to It. buscare "to filch, prowl," Sp. buscar (from O.Sp. boscar), perhaps originally from bosco "wood" (see bush), with a hunting notion of "beating a wood" to flush game. Busker mistakenly was derived from buskin in the stage sense.