1) For which reason 2) Ground 3) Reason 1) Whence 2) Wherefor 3) Why 
• (adv. & conj.) For what reason; why; -- used interrogatively. • (n.) the reason why. • (adv. & conj.) For which reason; so; -- used relatively.
Where'fore adverb & conj. [ Where + for .] 1. For which reason; so; -- used relatively. « Wherefore by their fruits ye shall know them.» Matt. vii. 20. 2. For what reason; why; -- used interrogatively. « But wherefore that I tel...Where'fore noun the reason why. [ Colloq.] 
[adv] - for which reason
why