# block up

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/block-up
Updated: 2026-04-24

## Definition

to fill a space or a pipe so that nothing can pass through it.

For teachers: to obstruct an opening, passage, or pipe completely, preventing the flow of liquids, air, or traffic.

## Examples

- Leaves often block up the drains in autumn.
- The sink is taking a long time to empty because hair and soap have started to block up the pipes.
- Heavy snowfall during the night threatened to block up the narrow mountain passes, effectively isolating the small village from the rest of the valley.

## Pitfalls

- Not "The drain is block up." but "The drain is blocked up." — when describing the state of the object, you must use the past participle 'blocked' as an adjective.

## Usage notes

- often used in the passive voice or with physical objects like pipes, noses, or roads.
- Teaching tip: contrast with 'block' (the simple verb); adding 'up' emphasizes the completeness of the obstruction or the gradual process of it becoming totally filled.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.