sardonic

the word 'sardonic' has a journey that traces back to the greek adjective 'sardonios', which was used to describe a bitter, scornful kind of laughter. this greek term was itself linked to 'sardanion', a poisonous plant found on the island of sardinia, ingestion of which was said to cause fatal convulsions resembling a grim, painful grin. the latin 'sardonius' carried this sense of a bitter, mocking smile into medieval and renaissance french as 'sardonique'. english adopted the word in the 17th century, preserving the core idea of a scornful, disdainful, and cynically humorous expression, but shedding the direct association with the poisonous plant, leaving only the powerful metaphor for a certain type of biting wit.

this word is a simplex form. it is a loanword adopted into english from french, which derived it from latin, and ultimately from a greek source. it is not productively formed from separable english morphemes.