(medicine, rare) Like the actions of a snarling dog, especially in reference to facial nerve paralysis.
1818, Matthieu Joseph Bonaventure Orfila, A Treatise on Mineral, Vegetable, and Animal Poisons, Considered as to their Relations with Physiology, Pathology, and Medical Jurisprudence:
Towards noon, he experienced convulsive movements; the extremities became stiff, the pulse extremely small, and he died during an attack of cynical spasm.
1857, New Orleans Medical News and Hospital Gazette – Volume 3, page 278:
On the contrary, in woman, the cynical spasm, though felt with as much, or even more violence than the other sex, is not followed with the same deleterious effects, and may be repeated much oftener without any unfavorable consequences.
1986, Giuseppe Roccatagliata, A History of Ancient Psychiatry, page 125:
Demetrius Attalicus studied the symptomatologies due to strictura cerebri, characterized by a cynical spasm of the facial nerve.
2009, Hilary Evans & Robert E. Bartholomew, Outbreak!: The Encyclopedia of Extraordinary Social Behavior, →ISBN:
Something of the same sort happened at Hensberg, Germany, where the nuns were afflicted and committed the sin they called “the silent sin.” In their ecstasies, their convulsions were very violent and interspersed with “cynical movements of the pelvis
Source: reddit.com/r/Erotica/comments/hfcw93/cynical_adjective_according_to_wiktionary