1 B1 neutral
To become or make a liquid or mixture thicker in consistency.
"Add a spoonful of cornflour to help the gravy thicken up."
separable
thicken up
B1 neutral separable transitive/intransitive
To become thicker in consistency, volume, or density, or to make something thicker.
In plain English
To get thicker — like when a sauce gets less watery as it cooks.
What does "thicken up" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B2 neutral
To become denser or more substantial in volume (hair, fog, crowd, etc.).
"The morning fog began to thicken up as they drove towards the coast."
Literal vs figurative
Words literally mean
To increase in physical thickness.
Actually means
To get thicker — like when a sauce gets less watery as it cooks.
Usage tip
Most common in cooking contexts. 'Up' emphasises completion of the process. Can also be used for hair, crowds, or fog becoming denser.
Words that pair with "thicken up"
Natural word combinations native speakers use most often.
sauce soup gravy hair fog mixture
How to conjugate "thicken up"
The five tense forms you'll use most often.
Base
thicken up
I/you/we/they
3rd person
thickens up
he/she/it
Past simple
thickened up
yesterday
Past participle
thickened up
have + pp
-ing form
thickening up
continuous
Hear "thicken up" in the wild
Listen to native speakers using "thicken up" in real YouTube videos — click a clip to watch it on Looplines.
Other ways to say "thicken up"
Swap in when you want variety — tap a linked one to explore it.
condense congeal reduce set thicken
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