cosplayPronunciation: /ˈkɒzpleɪ/Definition of cosplay noun [mass noun] the practice of dressing up as a character from a film, book, or video game, especially one from the Japanese genres of manga or anime. verb [no object] engage in cosplay. Derivatives cosplayer noun Origin: 1990s: blend of costume and playcosplay in other Oxford dictionaries Definition of cosplay in the US English dictionary