更新1:
in fact, it's a very usual usage... the origial meaning of the word is "lamer": http://www.zdic.net/cd/ci/6/ZdicE8Zdic80Zdic81321558.htm
更新2:
Lee, open the link i gave (it's an on line dictionary) and see 老外 meaning 外行 with your own eyes...
更新3:
ธนวัฒน์, perhaps what should be changed is not a dictionary?... because this dicionary is not the only one... btw are you sure black people from Africa aren't called "lao-wais"?... if not, what are they called then?