The story
- Proto-Germanic · inherited from*unmahtiz“inability; weakness”
- Old English · inherited fromunmiht
- Middle English · inherited fromunmight
- English todayunmight
From Middle English unmight, onmiȝt, from Old English unmiht, unmeht, unmeaht (“weakness; lack of power”), from Proto-Germanic *unmahtiz (“inability; weakness”), equivalent to un- (“lack or absence of”) + might. Cognate with Dutch onmacht, German Ohnmacht, Icelandic ómáttur (“unmight”).
Etymology from Wiktionary, CC BY-SA 4.0.