1. A reference to an increase of the acuteness or severity of a disease: Valerie's aunt was known to have spells of paroxysmal coughing which recurred periodically.
2. Relating to violent actions or emotions: Fits, extreme laughter or excitement, rage, and terror are paroxysmal responses to certain situations.
3. Pertaining to violent or convulsive physical actions: Examples of such paroxysmal activities include earthquakes or volcanic eruptions.