Cat*fish [kat-fish]: noun. 1. any of various fishes having a fancied resemblance to a cat. verb (used without object), verb (used with object) 2. Slang. to deceive, swindle, etc. by assuming a false identity or personality online: "He fell in love with her online before he realized he'd been catfished." 3. Slang. to advertise that your game has sweet wizards and skeletons and then have the game not deliver on that promise. "He fell in love with the box to Hydlide before he realized that the game inside was Hydlide."