Girls who cannot be identified as being hot or not. They often display some qualities of being hot (like big boobs), however, some qualities(such as a weird face) counter-act them.
J: "Woah, is Kellie hot or not, dude?! I thought she was, but..."
Drake:" I don't know; she's a Mystery Hot!"
Drake:" I don't know; she's a Mystery Hot!"
by LuLuBee November 7, 2010