Tic or twinge is a term used to describe a sudden, involuntary muscle SPASM. It can be caused by a variety of factors, including stress, fatigue, and even certain medical conditions. The crossword solution for this term is SPASM, which is an acronym for 'sudden, painful, and spasmodic muscle contraction'. This type of muscle contraction can cause pain and discomfort, and can sometimes be difficult to control.