What is the origin of interloper?
Interloper originally meant “unauthorized trader who trades on his own account and violates the rights or privileges of a trade monopoly.” It also has a tricky etymology. Inter-, its first element, is obviously the Latin preposition and prefix meaning “between, among.” The problem lies mostly with the second element -loper. Some authorities say that -loper is the same as in landloper “wanderer, vagrant,” an English borrowing from Dutch landlooper dating from about 1570. English interloper dates from the end of the 16th century, but a Dutch dictionary (1767) stated that the Dutch word enterlooper, phonetically equivalent to English interloper, is a borrowing from English. It is also difficult to reconcile an English word composed of the Latin prefix with the Dutch noun looper “runner.” It is more likely that -lope (and -loper) is a Middle English dialect variant of leap, ultimately from Old Norse hlaupa “to leap, spring, climb.” Interloper entered English on the late 16th century; the sense of “meddler” dates from the mid-17th century.