Related Clues:

• Muscle cramp, e.g.
• Muscle jerk
• Nervous mannerism
• A real jerk
• Start of a grid-based game
• Opening in "Hollywood Squares," essentially
• "___-Tac-Dough" (quiz show)
• First X, potentially
• Involuntary jerk
• ___ Tac (breath freshener)
• "Twitch," minus every other letter
• Tic or twinge
• Nervous twinge
• First O, maybe
• Tic, e.g.