Where does “deizmusuk” come from?

deizmusuk (Hungarian) comes from Hungarian deizmus, from German Deismus, from French déisme, from Latin Deus, from Latin dẹ̄vos, from Old Latin deivos, from Proto-Italic deiwos, from Proto-Indo-European deywós — to be bright; sky, heaven.

deizmusuk (Hungarian): third-person plural single-possession possessive...