We don't have a direct translation for moon, but you can hint at it with some clever rephrasing. You could try: "light of the night" (kunsevulon, kun do vulon).

If you're staying in the Elder Scrolls universe, you can use kunsemasser (kun do Masser) or kunsesekunda (Kun do Sekunda). Note: There is no "c" in Dovahzul so Secunda is Sekunda. In this context, Masser and Secunda are words loaned from other languages into Dovahzul, which doesn't have its own word for moon.

You could use Vulonsekun "Night light" . . .