Pathology . a sudden, abnormal, involuntary muscular contraction, consisting of a continued muscular contraction (tonic spasm) or of a series of alternating muscular contractions and relaxations (clonic spasm).

any sudden, brief spell of great energy, activity, feeling, etc.

noun

access , attack , burst , contraction , convulsion , eruption , frenzy , jerk , outburst , pain , paroxysm , seizure , throe , yank , cramp , shoot , agitation , cerebral palsy , clonicity , clonus , crick , fit , orgasm , palsy , pang , spell , tetany , tic , tonus , twitch