'assuage' originates from Old French, specifically the word 'assouagier', where the root meant 'to soften' or 'to make sweet'.

'assuage' changed from Old French 'assouagier' (and Medieval Latin 'assuaviare') and eventually became the modern English word 'assuage'.

Initially it meant 'to make sweet or soften', but over time it evolved into its current meaning of 'to lessen the intensity of (something unpleasant) or to relieve'.