
Middle English word whæt comes from Proto-Indo-European *kʷ-, Proto-Indo-European *kʷe-, Proto-Indo-European *kʷo-, Proto-Indo-European *kʷeh₁d-, and later Proto-Germanic *hwataz (Quick, sharp, brave.)
*kʷ- (Proto-Indo-European)
*kʷe- (Proto-Indo-European)
*kʷo- (Proto-Indo-European)
*kʷeh₁d- (Proto-Indo-European)
*kʷod (Proto-Indo-European)
*kʷh₁do- (Proto-Indo-European)
*kʷís (Proto-Indo-European)
Who, what (interrogative). Who, which, that (relative) Which, what.
*hwataz (Proto-Germanic)
Quick, sharp, brave.
*hwē (Proto-Germanic)
How, with what, by what means;.
hwæt (Old English)
Anything. What Now, indeed What!, listen!, hark!, lo!.
whæt (Middle English)