The story
- Old English · inherited fromstirnlīċe
- Middle English · inherited fromsternly
- English todaysternly
From Middle English sternly, sternely, sterneliche, sturnely, sturneliche, from Old English stirnlīċe, styrnlīċe, stiernlīċe (“harshly; severely; sternly”), equivalent to stern + -ly.
Etymology from Wiktionary, CC BY-SA 4.0.