To seal or block the entrance to a road, an area, or a building so that people cannot enter.(verb)
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Use "close off" in a sentence
"We caught a couple close off Berry Head, but she was still distrait; I silenced the flutter of the fish and cursed myself that we had gone ashore at all."
"The undulating leading edge, bristling shields and spears, threatened to close off her path."
"The rocky coastline of Argos was close off the port bow, and the fleet sailed on past small villages and ports, cutting toward the east and the islands southwest of Samothraki."