WHY, adv. L., for what. The original phrase is for what, for why.
1. For what cause or reason, interrogatively.
Turn ye, turn ye, for why will ye die? Jeremiah 27.
2. For which reason or cause, relatively.
No ground of enmity, why he should mean me ill.
3. For what reason or cause; for which; relatively.
Turn the discourse; I have a reason why I would not have you speak so tenderly.
4. It is used sometimes emphatically, or rather as a expletive.
If her chill heart I cannot move, why, Ill enjoy the very love.