undercover hater Posted in U Best definition undercover hater adjective/noun1. To secretly feel strong dislike or hostility towards: 2. A negative or critically person: Yo that triflin’ ho is an undercover hater for sure, bro. How satisfied are you with the definition? Looking for undercover hater meaning? Delighted that you discovered the greatest determine on our web site! Recently this definition was actually observed 16 times.