It can mean someone of non asian descent I guess...
From my past experience, a weeaboo or wapanese is someone who acts as if they are Japanese, although they are far from it. They speak in broken Japanese and excessively use the words, kawaii or baka, in normal conversation. They think they are Obsessive Otaku's, when they really are average fans. so there you go it's zuka's definition of wapanese.