1383 Hungary Denier - Counterfeit?

Hmm good question @ttk. In looking at similar examples on acsearch (and mine, below), they seem to be of relatively high percentage silver even though there is some surface staining consistent with copper content. However, your example is about half the weight of mine, so perhaps the silver was disproportionately leached out when this coin spent a lot of time in the ground? I'm not sure. If you live close to a university, it might be fun to befriend a professor who could put this into a scanning electron microscope and run a EDS analysis to see what elements are present.