why vs wherefore

why and wherefore both are nouns.

Word	Noun	Adjective	Verb	Adverb
why	Yes	No	No	No
wherefore	Yes	No	No	No

As nouns, why and wherefore are synonyms defined as:

why and wherefore: the cause or intention underlying an action or situation, especially in the phrase `the whys and wherefores'

why (noun)	wherefore (noun)
the cause or intention underlying an action or situation, especially in the phrase `the whys and wherefores'	the cause or intention underlying an action or situation, especially in the phrase `the whys and wherefores'