“Black sheep” is an idiom in that it is not meant to be taken for its literal meaning, but generally has a figurative meaning. The term is typically used to describe a person that doesn’t fit in with a specific group because of his or her behavior or appearance. It can also be used to refer to someone who is rebellious and doesn’t conform to ethics, morals, or beliefs of a particular group.
Although the term is not usually meant in a literal fashion, it does originate from a reference to the color of actual sheep. Due to a dominant gene trait, sheep generally have white wool. Occasionally, however, a recessive gene surfaces, and a sheep is born with black or dark-colored wool. The dark-colored sheep not only stands out from the crowd because of its appearance but can be considered as undesirable because black wool cannot be dyed like white wool.
Considering the origins of the phrase, when taken to the extreme, it can be used as a term of extreme disgrace. In other words, in some instances, if a person is referred to as a black sheep, it means that he or she has dishonored a particular group, such as his or her family. In that instance, the person is treated as undesirable and is looked upon as an outcast. More commonly, though, the term has softer connotations.
A person might be considered as a black sheep because of his or her physical appearance. For instance, if all members of a family are thin and athletic but one member is overweight and sluggish, that person might be labeled as the “black sheep.” The term might also refer to an individual’s behavior. As an example, if a group of employees on a job are all hardworking and dedicated but one member of the group is lazy and uninspired, he or she might be considered the black sheep of the group.
The term can also be used to refer to someone who is rebellious or defiant. That individual is typically labeled as the troublemaker within a group. For instance, a teacher might refer to a particular student in his or her class as a “black sheep” because of that student’s insubordinate or disruptive behavior.
Over time, the phrase has been adopted by organizations and groups to mark themselves as radical or extreme. For example, a particular Marine fighter squadron during World War II, known as Marine Attack Squadron 214, was nicknamed the Black Sheep Squadron because of their radical exploits during the war. The term has also been utilized in the area of psychology to describe how a group will judge their own nonconforming member more harshly than the nonconforming members of a rival group. This is known as the Black Sheep Effect.