seal off

Idioms  

1. 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.

---

Example Sentences

Working with Ukrainian authorities, the team from Gloucestershire aims to teach farmers how to seal off areas that are highly contaminated.

From BBC • Mar. 13, 2026

Schmidt said a proposed alternative had been to allow Deltopia to continue but to seal off Isla Vista to prevent out of towners from entering by using roadblocks and checkpoints.

From Los Angeles Times • Jan. 18, 2026

And it exposes something deeper about how the law handles its most final punishment: its willingness to seal off inquiry precisely when the stakes are highest.

From Slate • Jun. 26, 2025

The creatures then seal off the burrows at the ground line, where crawfish will survive “so long as there is some water on the bottom of that burrow,” Shirley explains.

From National Geographic • Feb. 15, 2024

He was trying to seal off the front of his cell by hanging plastic bags and blankets all over the bars—the smoke was that dense.

From "Newjack: Guarding Sing Sing" by Ted Conover

Related Words

• circle
• enclose
• surround