The story
- Old English · inherited from*hearmful
- Middle English · inherited fromharmful
- English todayharmful
From Middle English harmful, from Old English *hearmful (suggested by hearmfullīċ (“harmful; hurtful”)), equivalent to harm + -ful. Cognate with German harmvoll, Danish harmfuld, Swedish harmfull.
Etymology from Wiktionary, CC BY-SA 4.0.