unwelcome guest

• intruderUnauthorized person present
• trespasserUnlawful entrant on property
• crasherUninvited event attendee
• uninvitedWithout formal welcome
• gatecrasherUninvited event attendee

nuisance · pest · burden · impostor · overstayer · freeloader · squatter · awkward · intrusion · doorstep · lingering · unwanted · stranger · parasite · invader · outstay · encroach · tolerate