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Related to seal off: sealable
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To close, bar entry to, or isolate something very tightly or securely. A noun or pronoun can be used between "seal" and "off"; often used in passive constructions. The building was sealed off after an outbreak of a deadly virus occurred in the laboratory. The country sealed its borders off in response to the massive surge in migrants in the last week. He's been sealed off in his room ever since he started writing that novel of his.
Also, seal up. Close tightly or barricade to prevent entry or exit. For example, We're sealing off the unused wing of the building, or The jar is tightly sealed up. Dating from the first half of the 1900s, this idiom uses seal in the sense of "close securely," as one used to do with a seal of wax.
1. To close tightly or surround something or someplace with a barricade or cordon: The government has sealed off its borders. The police surrounded the building and sealed it off.
2. To isolate someone or something: The remote location sealed the village off from the rest of the world.