What is the idiomatic meaning of willy hilly?

"Willy hilly" is not a recognized idiomatic expression in English. It's possible that you've misheard or misspelled a phrase.

Could you provide more context or clarify what you're referring to?

For example:

* Did you hear it in a specific song or movie?

* What was the general context of the conversation where you heard it?

Knowing more about the situation will help me understand what you're looking for and provide a more accurate answer.