potlicker
/ˈpɒtˌlɪkər/Definitions
1. noun
an uninvited guest who attends a party or gathering, often to eat food
“She was upset that her ex-boyfriend was a potlicker at her birthday party.”
2. verb
to attend a social gathering or party in the hope of eating food, especially if invited to a meal
“He’s always potlicking at his coworker’s barbecues, eating all the free food.”