gatecrasher
One who attends an event, such as a concert, sports match, or party, without being invited or paying to get in. I don't mind gatecrashers coming to my parties, so long as they behave themselves. Due to the popularity of the show—and the limited amount of tickets—extra security was hired to keep any gatecrashers out of the concert. Those people are definitely gatecrashers, so please have one of the bouncers escort them off the premises.
party crasher
One who attends a party without having been invited. I don't mind party crashers coming to my parties, so long as they behave themselves.
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.