English Reference

Phrasal verb

clag up

Definition

phrasal verb. to become blocked or stuck with something thick and sticky so that a machine or system stops working well.

phrasal verb. to become obstructed or congested by a sticky or viscous substance; often used in mechanical or metaphorical contexts to describe a loss of efficiency.

Examples

“The printer keeps clagging up because of the cheap ink.”

“If you don't clean the filter regularly, it will clag up with dust and grease.”

“The gears began to clag up as the lubricant thickened in the freezing temperatures, eventually bringing the entire assembly to a halt.”

Examples

simple

“The printer keeps clagging up because of the cheap ink.”

contextual

“If you don't clean the filter regularly, it will clag up with dust and grease.”

complex

“The gears began to clag up as the lubricant thickened in the freezing temperatures, eventually bringing the entire assembly to a halt.”

Usage

often used with the preposition 'with' to name the substance causing the blockage.

Teaching tip

this is a more informal and vivid alternative to 'clog up' or 'block'; it is particularly common in British English and technical hobbyist circles.

Pitfall

The pipe clagged.

The pipe clagged up.

the particle 'up' is necessary to complete the meaning of becoming fully blocked.

Phrasal verb

Particles

up

Separability

optional

Pattern

clag + (object) + up

Synonyms

Antonyms

Grammar

This entry

Level
C1 · Advanced
Updated

Scan code

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English Reference