Gatecrashers are unwanted guests who show up at an event or party without an invitation. There are several synonyms for the term "gatecrashers" that can be used to describe such uninvited guests. Some common synonyms include party crashers, gatekeepers, uninvited guests, unwelcome guests, intruders, and trespassers. Other synonyms for gatecrashers include interlopers, freeloaders, moochers, and parasites. Using these synonyms can help to add variety and nuance to your writing, as well as make your language more dynamic and engaging. Whatever synonym you choose, it's clear that gatecrashers are never welcome, and it's important to know how to deal with them if they show up unexpectedly.