The story
- Old English · inherited from*batfull
- Middle English · inherited frombatful
- English todaybatful
From Middle English batful, badfull, perhaps from Old English *batfull, equivalent to bat (“to improve"; as in "battle, batten”) + -ful. Compare also Old Norse bati (“improvement, profit, usefulness”).
Etymology from Wiktionary, CC BY-SA 4.0.