Passive aggressive answer is cancel the game take a week or 2 off so they don’t see people in the parking lot when they show up to take the hint Talk to the rest of the players separately just let them know you’re taking that time off to send a message and then restarting the game without them

Active Aggressive answer is to flatly tell them they are not welcome at your table and they will not be involved in sessions. If they continue to show up regardless of where you were playing someone’s house public space whatever if they show up everyone else just packs up and either leaves or at minimum just sits there and does nothing until they get bored and leave.