A captain of a war vessel whose name appeared, or was "posted", in the seniority list of the navy.(noun)
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Use "post-captain" in a sentence
""I'll make Malcolm a post-captain in the navy and give you a thousand pounds," he said at length, hardly knowing that he spoke."
"Bay, and along the coast, should be left with an officer above the rank of post-captain -- especially, as the Russian and Turkish squadrons were soon expected in the bay -- he had thought it right to give Captain"
"He entered the sea service at an early age, and prospered as the sons of men of rank prospered in those days, being made a post-captain in 1747, when he was but three and twenty years old."