noun

1. a sudden, convulsive, involuntary muscular contraction: a tonic spasm is persistent and sustained, and a clonic spasm is one of a series of relatively brief contractions alternating with relaxations
2. any sudden, violent, temporary activity, feeling, etc.

Etymology: ME spasme < MFr < L spasmus < Gr spasmos < span, to draw, pull, wrench: see span

intransitive verb