The story
- Old French · derived fromampirement
- Anglo-Norman · derived fromempairement
- Middle English · inherited fromempeirement
- English todayimpairment
From Middle English empeirement, empeyrement, emparement, from Anglo-Norman empairement, emperement, enpeirement, from Old French ampirement, anpirement, enperement, equivalent to impair + -ment.
Etymology from Wiktionary, CC BY-SA 4.0.