Attested in Aelfric's Colloquy 1, Aelfric's Colloquy 2, Bede's Death Song, Aelfric's Colloquy 3, Aelfric's Colloquy 4

originates from: PGmc *hʷata- 'quick' (hʷata- > hʷat > hwat > hwæt) through pgmc-to-oe