- convulsive, spasmodic, spastic - affected by involuntary jerky muscular contractions; resembling a spasm; "convulsive motions"; "his body made a spasmodic jerk"; "spastic movements"
Antonym: steady (indirect, via unsteady)
- convulsive - resembling a convulsion in being sudden and violent; "a convulsive rage"; "convulsive laughter"
Antonym: nonviolent (indirect, via violent)