Funnily, "God" is most likely pagan in either origin that it is theorized to come from. It's either Germanic (pagan) or Indian/Vedic (also pagan). The Latin word Deus is a blatant rip-off of the Greek Zeus, which is also of Sanskrit influence from "dyaus," an adaptation of the Vedic "devas."
An appropriate name for the Judeo-Christian entity known as God is more likely Yahweh, much akin to Allah. The Latin "Jehovah" is a bad mispronunciation that is more often today spoken as "Juh-Hoe-Vah" rather than with a soft almost "i/y" sound for the J and a subdued "v" that is more of a "w."
Christians (or Jews, for that matter) don't claim the word "God" is a proper name, or that they invented it. We might use it like a name at times, but the Old Testament is pretty clear about God having a particular name, which He revealed to His followers. "God" was not that name. The word "God" is more like a title, which English-speaking Christians use, as it is an English term for, well, a god. I imagine the same goes for "Deus." Christianity, like most other religions that spread to other language groups, adopted local languages to express its teachings. (Although it was born speaking Aramaic, Hebrew, and Greek, so maybe it had a head start.) So there are many terms for the Deity of the Christian scriptures.
And "Jehovah" isn't Latin. It's a Latinization of the four consonants of the Hebrew
tetragrammaton (YHWH, in English).
