For all its recent history, the English word “god” is a fine old pagan word with a long, long pedigree.
Cognates occur in all Germanic languages (German Gott, Icelandic guð, etc.), and in all Germanic languages, interestingly, it was this word that was chosen by early missionaries to denote the Christian god. How and why this came to be is in itself an interesting question which would well merit further study, but that's not my intent here.
For historical reasons—largely because of its Christian associations—we've come to think of “god” as (connotatively, if not grammatically) masculine. I suspect that among English-speaking pagans this masculinization has been emphasized by the word's implied pairing with “goddess.” English lost its grammatical genders after the Norman invasion, but the other Germanic languages have kept all three of them (masculine, feminine, and neuter), and in all of them (again, for Christian reasons) the word god has become a grammatically masculine noun.
But that's not how the ancestors saw it.