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