Cosplay definition of cosplay by The Free DictionaryExplain cosplay in layman's terms. Costume play involves dressing up and pretending to be a specific character from an video game. It has become immensely popular among enthusiasts of geek subculture globally. Fans carefully create costumes and accessories to accurately portray their favorite characters. Cosplayers usually participate in gatherings or costume play events, where they can exhibit their creativity and network with others who share the same passion. Ultimately, cosplay is an manifestation of appreciation and commitment for a fictional character and the love for the geek community.