The worst thing I have ever been called in Japanese is ノンジャパ (non-Japa). Admin people at a university I attended long ago used it to refer to the foreign students.
I have never been fond of the English term "non-Japanese," either: Who wants to be defined in terms of what they aren't? More importantly, in Japanese it would be 非日本人 (hi-Nihonjin), which is rarely used.
No, I am a 外国人 (gaikokujin), which is best translated as "foreigner." Yes, some people still use 外人 (gaijin), but don't worry, I will not start another tedious debate about whether that term is offensive. I have a bigger problem with how it is used: Even the obscure 外賓 (gaihin, esteemed foreign guest) would be annoying if shouted by a finger-pointing 7-year-old boy while a bemused parent stood by doing nothing.