You don't need full-blown modern Windows inside VM to run Clipper, off-the-shelf DOS will do as well.
You can also try DOSBox.
Anyway - this Clipper app needs some data, where is this data coming from? Does it need networking? You have to answer (yourself) these questions first.
If I was you - I would get $50 XP box off eBay, and run that application. YOu are 15 years overdue for replacement of this app.