'second-rate' originates from the naval classification system, where ships were rated by their size and firepower. 'Second-rate' referred to ships that were not the largest or most powerful.

'second-rate' was used in the 17th century to describe ships that were not of the highest class, and eventually became a term for anything of inferior quality.

Initially, it meant 'a ship of the second class,' but over time it evolved into its current meaning of 'mediocre or inferior quality.'