spasm
nounA sudden, involuntary contraction of a muscle or group of muscles.
A sudden burst of energy, activity, or emotion.
Excessive muscular contraction.
In general, any sudden transitory movement of a convulsive character, voluntary or involuntary; an abnormally energetic action or phase of feeling; a wrenching strain or effort.
An involuntary and unnatural contraction of one or more muscles or muscular fibers.
