OK, this is a tough one. I think "while you are [supposed to be] away [from people]" is an overkill. This is one case where I would accept a transliteration followed by an explanation, but a correct one. Perhaps: "in a state of janabah (after ejaculation)"
I just don't want any transliteration if at all possible. جُنُب
means "farther out". Consider,
There you have the word used for the neighbor who is not immediately next to one's house, i.e., separated, isolated, etc. Therefore, it can be translated and if any word can be translated, it should not be transliterated.