Brass knuckles are a melee weapon used primarily in hand-to-hand combat. They are fitted and designed to be worn around the knuckles of the human hand. Despite their name, they are often made from other metals, plastics or carbon fibers and not necessarily brass.

Vajra-musti refers to a "fist-load, knuckleduster-like" weapon and also a form of Indian wrestling in which the weapon is employed. The weapon is sometimes called Indra-musti which means Indra's fist.