I agree that "he lives opposite" is the direct translation but also agree with Mr_Eyl that the direct translation doesn't make sense. Even so, I feel like this doesn't make much sense in German either.
Can a native speaker confirm: would you actually say it like this, or would you specify the object such as "Er wohnt gegenüber die Straße." Please and thank you!
As a native speaker (British) yes, I can confirm 'He lives opposite' is perfectly acceptable as an alternative way of saying ' He lives across the road'. You are right in that there should be an object , but this is often omitted as implicit. It doesn't even have to be a street... ' My girlfriend lives [in the flat] opposite.', or 'he is sitting [on the chair] opposite'.
I think we can all agree that this is a bit ambiguous. Yes, you can sometimes say "He lives opposite" and it is implied across "the way", "across the street" "across the road" "across the hall""across the footpath". Having said that...this kind of statement is usually made from the location in question. If you are in your apartment and pointing to your door...obviously you mean across the hall. If you are pointing out your window, you mean across the road, footpath, river or whatever. The only time I can recall that you don't need to be in the location of which you are referring..is if you say "he lives opposite me". Therefore, perhaps "opposite" is a better translation in this instance with "me" being implied. Thoughts?
I speak British English, living near London, and not American English. if some one knows where I live and asks if I know where someone else lives, I would always say that the person "lives opposite me" if that person was on the other (opposite) side of the road from me. If the person lived on the other side of the road but a few houses away, I would say, " Opposite side of the road to me, and a few houses left / right".
With "across", yes. In German, one can leave it implied (use just "gegenüber"), and the listener can use current location for context. In English, it doesn't work that way for the word "across"; the thing he lives across from should be supplied. As noted above, if one used "opposite" in English (i.e., "He lives opposite."), it would convey a similar feel and meaning, but is less frequently heard (in the US, at least).