wog (n.)

c. 1920, "a lower-class babu shipping clerk" [Partridge]; but popularized in World War II British armed forces slang for "Arab," also "native of India" (especially as a servant or laborer), roughly equivalent to American gook. Many acronym origins have been proposed, but none has been found satisfactory. Possibly shortened from golliwog, though Partridge Slang notes difficulties with this as the word was not originally applied to Black people. Nevertheless the derivation has been given as early as 1921.

The King Edward's Horse called the Indian Cavalry ‘The Wogs’—which is the diminutive of ‘Golliwogs’,—a description that was very apt of these dark apparitions in khaki and tin-hats. [Lt. Col. Lionel James, The History of King Edward's Horse, 1921. (Describing events of 1918.)]

By 1962, Peter Shaffer's play The Public Eye uses the term in reference to a British man of Greek descent. Woggy, used to describe anyone of non-Anglo-Celtic origin, is attested by 1968, in Australia. The saying "Wogs begin at Calais" is by 1971, and represents a sentiment that all non-British people are wogs. By 1986 it is defined in Lexicographic Description of English as "a dark skinned foreigner." Irvine Welsh's book Trainspotting (1993) references porridge wogs as a slur for Scottish people. Related: Wogland.