loser gesture
A gesture formed by extending the index finger and thumb into the shape of an L, then bending all other fingers back and placing the hand against the forehead.
Famously referenced in the first verse of the song "All Star" by the band Smash Mouth: "She was looking kind of dumb with her finger and her thumb / In the shape of an "L" on her forehead"
This tag implicates hand_gesture (learn more).