'assuagement' originates from Old French, specifically the verb 'assouagier' (also spelled 'assoagier'), ultimately built from Latin elements such as 'ad-' and 'suavis', where 'ad-' meant 'to' and 'suavis' meant 'sweet.'

'assuagement' changed from Middle English forms such as 'asswagement' (borrowed from Old French 'assouagier') and eventually became the modern English noun 'assuagement' formed from the verb 'assuage' plus the suffix '-ment.'

Initially the root sense was roughly 'to make sweet' or 'to lessen harshness'; over time it evolved into the current meaning of 'relief, mitigation, or easing of distress.'