1 B1 neutral
To close a container, package, or opening completely and securely
"She sealed up the envelope and left it on his desk."
separable
seal up
B1 neutral separable transitive
To close something completely and securely, making it airtight, watertight, or impossible to open
In plain English
To close something so tightly that nothing can get in or out
What does "seal up" mean?
3 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B1 neutral
To fill or cover gaps, cracks, or holes in a structure to make it airtight, watertight, or weatherproof
"They sealed up the cracks around the windows before winter to stop the draughts."
separable
3 B2 idiomatic informal
(Figurative) To suppress or lock away emotions, memories, or feelings
"After the divorce, he sealed up all his grief and threw himself into work."
separable
Literal vs figurative
Words literally mean
To seal (close completely) something up — fairly transparent; 'up' intensifies the completeness of the action
Actually means
To close something so tightly that nothing can get in or out
Usage tip
Used for practical tasks like sealing envelopes, packaging, gaps in windows, or buildings. 'Up' emphasises completeness. Also used figuratively for closing off emotions or memories.
Words that pair with "seal up"
Natural word combinations native speakers use most often.
envelope gap crack box container wound
How to conjugate "seal up"
The five tense forms you'll use most often.
Base
seal up
I/you/we/they
3rd person
seals up
he/she/it
Past simple
sealed up
yesterday
Past participle
sealed up
have + pp
-ing form
sealing up
continuous
Hear "seal up" in the wild
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Other ways to say "seal up"
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