Noun; any kind of authority figure. Anyone with authority over a child or teenager. Any one with the power to prohibit you to do something or discipline you for doing something. (A parent, guardian, teacher, counselor, etc.)
Yo man, we can't light up right now, the shak will be back any minute now.
If there were no shaks, life would be a party.
Teen: Yo can I go to this party?
Shak: Is there parental supervision?
Teen: Uh, yeah whatever.
Shak: Let me talk to the parents
Teen: F*** you, you F***in B*** go S*** a C***