interloper
Pronunciation:
[ˌɪntəˈləʊ̯pə][ˌɪntɚˈloʊ̯pɚ]noun
Definitions
An unlicensed or illegitimate trader.
One who interferes, intrudes or gets involved where not welcome, particularly a self-interested intruder.
Example: They disliked the interloper, and forced him to leave.