Definition of post captain in English:

post captain

noun

historical
  • A Royal Navy officer holding the full rank of captain, as opposed to a commander with the courtesy title of captain.

    • ‘I can't resist pointing out that a master and commander would never captain a frigate, and quite properly the film has Aubrey wearing the two epaulettes of a post captain.’
    • ‘He had made post captain when he was only twenty-three years old, not an unheard of feet, but he had been young enough to be hailed as one of the most promising officers in the King's service.’