- intruder, interloper, trespasser - someone who intrudes on the privacy or property of another without permission
--1 is a kind of entrant; unwelcome person, persona non grata
--1 has particulars:boarder; gatecrasher, crasher, unwelcome guest; infiltrator; invader, encroacher; penetrator; prowler, sneak, stalker; pusher, thruster; squatter; stranger, alien, unknown Derived forms: verb intrude2, verb intrude1