Blackball is a compound of black + ball, from the practice of placing a black ball in a ballot box to vote against a candidate's admission to a club. The historical trail runs through blæc in Old English. Morphologically, blackball is transparent: it is a compound of black + ball, from the practice of placing a black ball in a ballot box to vote against a candidate's admission to a club. Used as a verb and noun, blackball now means "reject or exclude someone, especially by voting against their membership", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in related forms such as black and ball. The modern word remains analyzable through its parts, which makes the semantic connection unusually direct.