One who interferes, intrudes or gets involved where not welcome, particularly a self-interested intruder. / (obsolete) An unlicensed or illegitimate trader.

plural of interloper

An act of intrusion or encroachment. / (historical) Illegal Indian trade within the area over which the Hudson's Bay Company held a trade monopoly.

present participle of interlope

To intrude, meddle, or trespass in others' affairs.

simple past tense and past participle of interlope

Third-person singular simple present indicative form of interlope

plural of interloping

intrusion