fatten up
In real, traceable use. Part of the curated seed collection; community review is coming.
Sense 1
Meaning · English
To cause to gain weight by means of feeding.
Where it’s used:
Used
American English
Examples
My cat looks underweight, so I'll fatten him up with higher-calorie cat food.
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Sense 2
Meaning · English
To become fat or fatter by gaining weight.
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Sense 3
Meaning · English
To make bigger; to expand.
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-07-30 via kaikki.org).
Common questions
What does “fatten up” mean?
To cause to gain weight by means of feeding.
Is “fatten up” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.