interloper

Etymology
1590s, from, as in (from  (originally dialectal)). Originally spelt and used in specific sense “unauthorized trader trespassing on privileges of chartered companies”, later general sense of “self-interested intruder” from 1630s.

Noun

 * 1) One who interferes, intrudes or gets involved where not welcome, particularly a self-interested intruder.
 * They disliked the interloper, and forced him to leave.
 * 1)  An unlicensed or illegitimate trader.
 * 1)  An unlicensed or illegitimate trader.

Translations

 * Dutch:
 * Finnish: ,
 * French:
 * German:
 * Hungarian:
 * Icelandic:, aðskotadýr
 * Italian:
 * Macedonian: натрапник
 * Maori: kaiauwaha, kaihūrau
 * Norwegian:
 * Bokmål: inntrenger
 * Polish:
 * Serbo-Croatian:
 * Spanish: ,
 * Swedish: