CharlieyoudaoicibaDictYouDict[Charlie 词源字典]
masc. proper name, familiar form of Charles (also see -y (3)); 1965 in Vietnam War U.S. military slang for "Vietcong, Vietcong soldier," probably suggested by Victor Charlie, military communication code for V.C. (as abbreviation of Viet Cong), perhaps strengthened by World War II slang use of Charlie for Japanese soldiers, which itself is probably an extension of the 1930s derogatory application of Charlie to any Asian man, from fictional Chinese detective Charlie Chan.

Other applications include "a night watchman" (1812); "a goatee beard" (1834, from portraits of King Charles I and his contemporaries); "a fox" (1857); "a woman's breasts" (1874); "an infantryman's pack" (World War I); and "a white man" (Mr. Charlie), 1960, American English, from black slang.[Charlie etymology, Charlie origin, 英语词源]