Butt naked, perhaps a misinterpretation or regional version of buck naked, is an idiom referring to a complete state of undress. The buck part has been thought to refer to various permutations such as a young dandy, a Native American or a male slave, but most likely comes from a term for buttocks. No one is quite sure where it originated. Joshua Milton Blahyi, a Liberian pastor and former warlord, earned the nickname “General Butt Naked” for his fighting style during the Liberian tribal war.
Idioms are expressions in which the words don’t mean exactly what they say, but in the case of butt naked, the meaning seems to be a bit more literal. In the Southern US, butt naked is used frequently along with butt-ass naked, bare-ass naked, and ass naked. This leaves no doubt that current use of the phrase refers to someone who is totally nude. The use of buck in the phrase is also thought to be a polite substitution for the more crude word butt.
There are conflicting theories as to the origin of the phrase, which was first heard in the 1920s. It has been found in novels dating from that time. Buck was used instead of butt, so indeed it may be the older version of the idiom. A slang word for buttocks, bucket, may have also been employed at the time and shortened into buck.
Others attribute the phrase to older origins, referring to the extremely nude condition of a de-hided deer. A common Anglo-Saxon reference for a male deer is a buck. This word was later used to refer to other male animals and eventually to male humans. Buck as a synonym for dandy, a man overly concerned with his appearance, has been heard since the 1700s. The derogatory usage for male blacks and Native Americans came later.
During the Liberian Civil War between 1989 and 2003, a young man named Joshua Milton Blahyi made a reputation for himself as a ruthless and unusually cruel guerilla leader. Elected as a high priest of the Khani tribe at the age of eleven, Blahyi and his troops would charge into battle nude, wearing only boots and carrying machine guns. They earned the nickname “Butt Naked Brigade,” and Blahyi became known as “General Butt Naked.” After becoming a pastor and claiming to be reformed, Blahyi confessed to his war crimes in 2008. The phrase butt naked is a fearful one for many Liberians.