Sistard sĭs'tärd' - noun - female offspring having both parents in common with another offspring; also a female sibling; that is also slow, dimwitted, and/or appears mentally challenged with the severe level of intelligence deficiency, yet is allegedly cognitively normal according to the standards set by society.
Brice sits on his ass all day masturbating. Then he goes to dinner and can't hold his own bowel movement, so he has to shit right outside the Denny's. He is such a SHITTARD.