riled

The verb 'rile' is an 18th-century American English variant of 'roil', meaning to make a liquid cloudy or muddy by stirring up sediment. The figurative sense of disturbing someone's mental calm, thus irritating or annoying them, developed naturally from this literal meaning. 'Roil' itself likely entered English from the now-obsolete French verb 'ruiler', meaning to roll or flow turbulently, which may have roots in Vulgar Latin. The past participle 'riled' became a standard adjective to describe a state of agitation or annoyance, completing the semantic journey from turbulent water to ruffled temper.

The word 'riled' is a simplex form derived from the verb 'rile'. It is not productively segmented into smaller, meaningful morphemes in modern English.