paroxysm.

From Late Middle English paroxism, paroxisme (“period of worsening of a disease, attack; sudden recurrent fever”), from Middle French paroxisme, paroxysme, and Old French peroxime (“period of worsening of a disease; bout of fever or illness”) (modern French paroxysme), and from their etymon Late Latin paroxismus, paroxysmus (“a fit; onset of a disease; violent impulse or sadness”), from Ancient Greek πᾰροξῠσμός (păroxŭsmós, “exasperation, irritation; severe fit of a disease”), from πᾰροξῡ́νω (păroxū́nō, “to irritate, provoke”) (from παρα- (para-, prefix meaning ‘parallel to but separate from or going beyond, beside’) + ὀξῡ́νω (oxū́nō, “to provoke; to sharpen”) (from ὀξῠ́ς (oxŭ́s, “sharp”), probably ultimately from Proto-Indo-European *h₂eḱ- (“sharp”))) + -μός (-mós, suffix forming abstract nouns). By surface analysis, para- + oxy- + -ism.