Whȳ1, adv.
(hwī), adv. [A-S. hwy, hwê, hu, why, instrum. of hwa, hwät, who, what; Icel., Sw., & Dan. hvi, Goth. hvê, du-hvê.]
Sense 1. For what cause, reason, or purpose; on what account; — used interrogatively.
Turn ye from your evil ways, for why will ye die? Ezek. xxxiii. 11.
Sense 2. For which reason or cause; on which account; on account of which; for what; — used relatively.
No ground of enmity, Why he should mean me ill. Milton.
Turn the discourse; I have a reason why I would not have you speak so tenderly. Dryden.
Sense 3. The reason or cause for which; that on account of which; as, I know not why he left town so suddenly; — used as a compound relative.
☞ Why is used sometimes emphatically, or as an expletive.
If her chill heart I can not move, Why, I'll enjoy the very love. Cowley.
For why, for what reason; why. [Obs. or colloq.]