A Lindsey
When you look up a word on Urban Dictionary and it's exactly how you used it, but you still act like you're the smartest person in the room.
Lindsey: 'I don't even know what that means!' (she just used the exact definition.)
Urban Dictionary says 'A Lindsey' is when you act like you're genius but you're not.
She looked up 'A Lindsey' and then said she didn't know what it meant.