an uncontrollable outburst: a paroxysm of giggling
2.
pathol
a. a sudden attack or recurrence of a disease
b. any fit or convulsion
[C17: via French from Medieval Latin paroxysmus annoyance, from Greek paroxusmos, from paroxunein to goad, from para-1 (intensifier) + oxunein to sharpen, from oxus sharp]