The story
- Latinabōminābilis
- Old Frenchabominable
- Middle Englishabhomynable
- Englishabominable
- English todayabominably
From abominable + -ly.
First known use, by meaning
- First attested around 1350 to 1470. In an abominable manner; very odiously; detestably.
Etymology from Wiktionary, CC BY-SA 4.0.