Brickbat is a compound of brick + bat ('a lump, piece'), originally denoting a fragment of brick thrown as a missile; the figurative sense 'a critical remark' arose by extension. Morphologically, brickbat is transparent: it is a compound of brick + bat ('a lump, piece'), originally denoting a fragment of brick thrown as a missile. Used as a noun, brickbat now means "a piece of brick used as a missile; a blunt verbal insult or criticism", 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 brick and bat. The modern word remains analyzable through its parts, which makes the semantic connection unusually direct.