affected by involuntary jerky muscular contractions; resembling a spasm; "convulsive motions"; "his body made a spasmodic jerk"; "spastic movements" resembling a convulsion in being sudden and violent; "a convulsive rage"; "convulsive laughter
A convulsive movement or action is sudden and cannot be controlled. She thought she could never stop until convulsive sobs racked her even more. a convulsive movement or action is sudden, violent, and impossible to control