The story
- Old English · inherited from*plihtlīċe“dangerously”
- Middle English · inherited fromplihtliche
- English todayplightly
From Middle English plihtliche, from Old English *plihtlīċe (“dangerously”), from plihtlīċ (“dangerous, perilous”), equivalent to plight + -ly.
Etymology from Wiktionary, CC BY-SA 4.0.