WHY, adverb [Latin , 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 27:13.

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.