Kiim 'wife' would unfortunately be the closest, as dragons don't have a wide vocabulary surrounding romance or sexuality. You could say vahdin-fahdon "maiden-friend", something of an approximation of "girlfriend" or "lady-friend", or kiim-fahdon "wife-friend" to imply a friend who is like a wife, but not actually one's wife. I wouldn't recommend using zeymahzin 'companion' as that is more closely associated with battle.

Thank you very much. I realize this may come across as "poking"--please do not take it that way. Dovahzul, like all language, has  it's purest form (that which originated with the Dov), but also has an evolved form (that which was passed to men). It is clear from the canon that men took this language, and created new words not known previously to the dov (hence, the Dragonrend shout). To that end, I don't think it is improper to consider a set of words that speak to the basic nature of man (ie. love, hate, sex, freedom, captivity, etc). But this is an aside. To the point I raised above:

Thank you Paarthurnax. I appreciate how you are attempting to get to "girlfriend" from the canon words available. From my own understanding, I was thinking that something along the lines of ko (in) vahdin (maiden) -iil (possessive) would be something of the trick. I realize this might come across...bluntly...perhaps vulgar...but I really was attempting to come up with something that denoted sexuality. Is it proper to display my cobbled together word as kovahdiniil?

why are numbers bieng inserted into my text??

((also, for background, I'm writing a book, and in one place a question is asked, in dovahzul, "is she your lover?"))

I don't think a word currently exists. The canon holocaust means that words that dragons wouldn't need or understand have been eradicated.