"Nigger in the woodpile" or "nigger in the fence" is a figure of speech originating in the United States meaning "some fact of considerable importance that is not disclosed—something suspicious or wrong".[1]
Commonly used in the late 19th and early 20th centuries, its usage has since drastically declined, owing to its use of the ethnic slur nigger, and use of the phrase by public figures has often been criticized because of the usage of the slur in the term.