what for

not-comparable colloquial

For what purpose. / (colloquial) For what reason; why.

Japanese Meaning

何のために / どのような目的で / どういう理由で

He bought a ladder, but I still don't understand what for.

彼ははしごを買ったが、私はまだ何のために買ったのか理解できない。

Sense（1）

For what purpose.

What is this tool for?

Sense（2）

(colloquial) For what reason; why.

He wants four copies of it? What for?