Slang phrase nigger from the woodpile "a hid motive or mysterious variable influencing a situation within an adverse way" [OED 1989] is attested by 1800; Thornton's "American Glossary" (1912) defines it as "A manner of accounting for that disappearance of gas," for this reason "an unsolved thriller.The slang phrase "Niga" is usually a very offensiv