Task: Explanation
Input (English): Gweilo or gwailou (, pronounced ] ) is a common Cantonese slang term for Westerners. In its unmodified form, it applies only to European ethnicities and has a history of racially deprecatory use. Cantonese speakers frequently use "gwailou" to refer to Westerners in general use, in a non-derogatory context, although whether this type of usage is offensive is disputed by both Cantonese and Westerners alike. Question: The title of the Ghosts film is a reference to what Cantonese slang term that is used in Cantonese to refer to Westerners, and applies to European ethnicities in its unmodified form. Answer: Gweilo
Output (English):  In its unmodified form, it applies only to European ethnicities and has a history of racially deprecatory use.