How to make a stroke transparent

Because your title asks about making a stroke transparent, is the problem that you’re trying to change the opacity of the stroke and fill separately?

If you want to make the entire object transparent, use Jacob’s answer. You can also set whole object opacity in the Properties panel.

If you want to set transparency of the stroke and fill separately, in the Appearance panel expand the Opacity section for Stroke and/or Fill as needed, then click that component’s underlined Opacity value to adjust it independently.

midnightstarr,

As I (mis)understand it, with the big hexagon selected, change the Opacity to a suitable value lower than 100% in the Transparency panel.

Please show an example.