What size is this hoodie?

It is listed as size M, but the measurements are the better guide: 22 inches pit to pit, 20 inches pit to cuff and 28 inches collar to hem. Compare those with a hoodie that fits you well.

What condition is it in?

It is described as in good used condition. That means it has been worn before, so expect some signs of use rather than a new garment.

The material is not specified. Jordan hoodies of this style are typically cotton or a cotton-poly fleece blend, but confirm the fabric before buying if that matters to you.

Is this a pullover or a zip-up?

It is a pullover hoodie. No zipper is described.

How does it compare with a new Jordan hoodie?

A new one gives you an unworn garment and a known size label. This one gives you exact measurements and a specific purple colorway, but with used condition and no fabric details.