What is brickbats?

Brickbats are small pieces of broken bricks used as a projectile or as a way of expressing disapproval or criticism. The term is often used metaphorically to refer to any kind of negative criticism or feedback. In the construction industry, brickbats are sometimes used as a lightweight building material or as a base for roads and other structures. However, they are not generally considered to be a reliable or durable material, and are frequently replaced with more modern materials such as concrete or asphalt. In some parts of the world, the term "brickbat" is also used to refer to a particular type of hand grenade.