The story
- Middle English · derived fromben ware“to be on one's guard, be vigilant”
- Middle English · inherited frombewar
- English todaybeware
From Middle English bewar, be war, be ware, forms of Middle English ben ware (“to be on one's guard, be vigilant”, literally “be ware”), equivalent to be + ware or be + aware. Compare Old English bewarian.
Etymology from Wiktionary, CC BY-SA 4.0.