'heavyweight' originates from modern English as a compound of 'heavy' and 'weight'; 'heavy' originates from Old English 'hefig', where 'hefig' meant 'heavy', and 'weight' originates from Old English roots related to Proto-Germanic terms for 'weight' or 'heaviness'.

'heavyweight' arose as a compound in English; it became a technical term for a weight class in pugilism and organized sports in the 18th–19th centuries and later extended to figurative uses for people or organizations of great power or importance.

Initially a literal description of large mass or body weight, it evolved into a technical sports term denoting the highest weight class and later into a figurative sense meaning 'persons/organizations of great influence or power'.