whyever

(interrogative, без степеней сравнения)Why ever: an emphatic form of why.

Whyever would someone do that?

(без степеней сравнения, нечастое)For whatever reason.

You can use it whenever you want and whyever you want.

(без степеней сравнения, нечастое)Regardless of the reason (why).

I don't care what you want. Whyever you're here, please go away.