i Register
In some senses, third-rate is marked as UK, historical, idiomatic. Watch for register when choosing this word.
adj
Of a Royal Navy ship of the line in the Napoleonic Era: having 64–80 guns across two gun decks, a complement of 500–650, and weighing approximately 1,750 tons burthen.
Poor, shoddy; less than second-rate.
He was smoking a cherry-wood pipe, and looked on the whole as if he had borrowed his outfit from the wardrobe of a third-rate dramatic company.
I consider it to now be a third-rate service run without any excuses being offered.
noun
A third-rate ship of the line.