1. 间歇的;一阵阵的
Something that is spasmodic happens suddenly, for short periods of time, and at irregular intervals.

1. occurring in spells and often abruptly

e.g. fitful bursts of energy
spasmodic rifle fire

Synonym: fitful

2. affected by involuntary jerky muscular contractions
resembling a spasm

e.g. convulsive motions
his body made a spasmodic jerk
spastic movements

Synonym: convulsivespastic