spasmodic

adj

1. Of or relating to a spasm; resembling a sudden contraction of the muscles.
2. Convulsive; consisting of spasms.

   “spasmodic asthma”

   “[…] Dr. Francis Fuller, […] upon wearing a Quick-ſilver Girdle, for the Cure of the Itch, (and that after an inconſiderate and raſh manner) was brought under a violent Spaſmodick Diſtemper, which was ſupposed by himſelf and others to be owing to ſome Mercurial Particles lodg'd in ſome excretory Ducts of the Brain.”

   “Kennedy’s vocal rasp is not caused by an infection or respiratory condition. Instead, he has spasmodic dysphonia, a rare neurological condition in which the muscles that open and close his vocal cords spasm involuntarily, creating a strained or strangled quality to his speech.”

3. Intermittent or fitful; occurring in abrupt bursts.

   “spasmodic zeal or industry”

   “The chin was heavy, the nostrils were low and wide, and the lower lip hung loosely except in his moments of spasmodic earnestness, when it shut like a steel trap.”

4. Erratic or unsustained.
5. Of or relating to the spasmodic poets, a group of British Victorian poets who wrote introspective drama in verse.

noun

1. A medicine for suppressing spasms.