Why etymology

English

English word why comes from Proto-Indo-European interrogative roots *kʷ-, *kʷe-, *kʷo-, and later Proto-Germanic *hwī (how, with what, by what means)

Detailed word origin of why

Dictionary entry Language Definition
*kʷ- Proto-Indo-European (ine) Primary interrogative root in Indo-European
*kʷe- Proto-Indo-European (ine)
*kʷo- Proto-Indo-European (ine)
*kʷód, kʷod Proto-Indo-European (ine)
*hwī Proto-Germanic (gem-pro) How, with what, by what means;.
*kʷís Proto-Indo-European (ine) Who, what (interrogative). Who, which, that (relative) Which, what.
*hwē Proto-Germanic (gem-pro) How, with what, by what means;.
hwā Old English (ca. 450-1100) (ang)
hwī Old English (ca. 450-1100) (ang)
why Middle English (1100-1500) (enm)
why English (en) An exclamation used to express indignation, mild surprise, or impatience. "Well, I'll tell you...". Reason For what cause, reason, or purpose.. Introducing a complete question.. Introducing a noun or other phrase.. Introducing a verb phrase (bare infinitive clause).

Words with the same origin as why

Descendants of *kʷ-

however quality weather where who whom