The Collaborative International Dictionary of English v.0.48:
Paroxysmal \Par`ox*ys"mal\, a. Of the nature of a paroxysm; characterized or accompanied by paroxysms; as, a paroxysmal pain; paroxysmal temper. -- Par`ox*ys"mal*ly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
paroxysmal adj 1: accompanied by or of the nature of paroxysms