Definition of "unwelcome guest" []

• Someone who gets in (to a party) without an invitation or without paying (noun)

WordNet. Princeton University. 2010.

• "Johnny Livingstone had promised to make him the bed and some more chairs, but his unwelcome guest was going to prove expensive."
• "‘That’s up to you,’ said Blake, relinquishing Nora to her uncertain balance as he moved to see his unwelcome guest on her way, ‘but before you blow this trivial encounter out of proportion, you might want to consider whether you want it known that you intruded into my love-nest under the mistaken impression that you’d be welcome."