Black sheep

"Black sheep" is a derogatory colloquialism meaning an outsider or one who is different in a way which others disapprove of or find odd. This can be someone who has been shunned by others, or one who has chosen to be an outsider, due to actions and aims that separate them from the rest of the people or "flock".

Guinan once recalled a fond relationship with her uncle Terkim despite his being the black sheep of her family.