Brewer's: Sardonic Smile, Grin, or Laughter
A smile of contempt: so used by Homer.
“The Sardonic or Sardinian laugh. A laugh caused, it was supposed, by a plant growing in Sardinia, of which they who ate died laughing.” —
The Herba Sardonia (so called from Sardis, in Asia Minor) is so acrid that it produces a convulsive movement of the nerves of the face, resembling a painful grin. Byron says of the Corsair, There was a laughing devil in his sneer.
`Tis envy's safest, surest rule To hide her rage in ridicule; The vulgar eye the best begniles When all her snakes are decked with smiles, Sardonic smilesby rancour raised.