Sentence:  Thus, when another <WSD>party-goer</WSD>, Robert, arrived just as the cake-cutting ceremony ended, wearing a “Free Pee Wee” T-shirt that featured a black-and-white mug shot of Reubens beside an innocently smiling Pee Wee, people clustered around to ask about getting the shirt. 
Meaning of the word marked with <WSD> tags:  One who attends a specific party.