This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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n. A sudden outburst of emotion or action: a paroxysm of laughter.

n. A sudden attack, recurrence, or intensification of a disease.

n. A spasm or fit; a convulsion.

n. A random or sudden outburst (of activity).

n. An explosive event during a volcanic eruption.

n. A sudden recurrence of a disease.

n. The fit, attack, or exacerbation, of a disease that occurs at intervals, or has decided remissions or intermissions.

n. Any sudden and violent emotion; spasmodic passion or action; a convulsion; a fit.

n. In medicine, a fit of any disease; periodical exacerbation of a disease.

n. Hence Any sudden and violent action; spasmodic affection or action; convulsion; fit.

n. Figuratively, a quarrel.

n. a sudden uncontrollable attack

"Her innards were in paroxysm, violently expelling what they no longer recognized as food."

attack   

paroxysmal   

convulsion    fit    ecstasy    spasm   

spasm    twinge    throes    outburst    frenzy    tremor    undercurrent    spurt    brimful    surge