# clog up

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/clog-up
Updated: 2026-10-22

## Definition

to block a pipe, road, or system so that things cannot flow through it. You use this when hair blocks a drain or too many files slow down your computer.

For teachers: to obstruct a channel, conduit, or system through the accumulation of material. This phrasal verb is frequently used in both literal and figurative contexts.

## Examples

- Too much fat can clog up your arteries.
- The heavy snowfall started to clog up the main roads, making it impossible for buses to finish their routes.
- Administrative bureaucracy tends to clog up the system, preventing essential resources from reaching the frontline workers who need them most during a national crisis.

## Pitfalls

- Not "The pipe is clogged up of dirt." but "The pipe is clogged up with dirt." — Use the preposition 'with' to name the substance causing the blockage.

## Usage notes

- Often used with 'with' to indicate the substance causing the blockage.
- Teaching tip: Contrast with 'block' and 'congest'; 'clog up' often implies a messy or gradual accumulation of waste or unwanted items.

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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.