1. affected by involuntary jerky muscular contractions; resembling a spasm (Freq. 2) - convulsive motions - his body made a spasmodic jerk - spastic movements • Syn: spasmodic, spastic • Similar to: unsteady • Derivationally related forms: spasticity (for: spastic), convulse 2. resembling a convulsion in being sudden and violent (Freq. 1) - a convulsive rage - convulsive laughter • Similar to: violent • Derivationally related forms: convulse