Hong Kong term for (white)
Westerners.
It means something like "ghost", "ghost man" in Cantonese.
Not really an insult, sort of funny, almost endearing.
Can be an insult when used with "sei": "sei gweilo", means "damned foreigner"
Also spelled as gweilo or gwailo.
A
western woman is called "kweipo" (or gweipo/gwaipo).