Double movement. Dominant flat hand (or relaxed 5 hand) taps tip of thumb of stationary non-dominant "5"-hand.
SENIOR-(academic)
Sample sentence: Senior girls are stuck up. Why?
Notes:
I don't believe that senior girls are stuck up. This sentence simply provides a good opportunity to practice various other signs:
MOST
See: FRESHMAN
See: JUNIOR
See: SOPHOMORE
Notes:
The sign SENIOR-(academic) doesn't mean the same as "senior citizen."
If you mean "senior citizen" see: SENIOR-CITIZEN
Notes: