Hi,
There is no such thing, but it's not really needed.
When you go in the "variants" tab of your product, you can delete the variants you don't want.
So if you don't want the value Y of the characteristic 2 when you select the value X of the characteristic 1, simply unpublish or delete the variant X / Y from your variants listing and that choice won't be purchasable even though other variants with X and another value of the characteristic 2, or with Y and another value of the characteristic 1 will still be available.