fatten

American  

[fat-n] / ˈfæt n /

verb (used with object)

1. to make fat.

2. to feed (animals) abundantly before slaughter.

3. to enrich.

   to fatten the soil; to fatten one's pocketbook.

4. Cards.

   1. Poker. to increase the number of chips in (a pot).

   2. Pinochle. to play a card that scores high on (a trick) expected to be taken by a partner.

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verb (used without object)

1. to grow fat.

fatten British  

/ ˈfætən /

verb

1. to grow or cause to grow fat or fatter

2. (tr) to cause (an animal or fowl) to become fat by feeding it

3. (tr) to make fuller or richer

4. (tr) to enrich (soil) by adding fertilizing agents

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Other Word Forms

• fattenable adjective
• fattener noun
• fattening adjective
• overfatten verb (used with object)

Etymology

Origin of fatten

First recorded in 1545–55; fat + -en ¹

Explanation

To fatten someone is to feed them until they become bigger and fatter. Your grandmother might see a tiny baby and say, "His mother needs to fatten him up!" A farmer might spend weeks trying to fatten his prize pigs before he sells them for meat, and you may visit relatives who keep cooking you delicious food in an attempt to fatten you up. Figuratively, you can also fatten things like your bank account, by making it larger. Before the 1550s, the verb form of this word was fat — and both fat and fatten come from the Old English word fætt, "fat or plump."

Example Sentences

It’s also possible that retailers, figuring that consumers would expect to pay more for tariffed washing machines and would assume the same effect held for dryers, charged more for the latter to fatten their profits.

From Los Angeles Times • Feb. 24, 2026

Feeders are ranchers who own feedlots where they fatten cattle and sell them to meatpackers.

From The Wall Street Journal • Dec. 24, 2025

James Canton spent two years sitting beneath an 800-year-old oak tree near his home in Essex, watching acorns fatten and butterflies land on the massive knurled grey trunk.

From BBC • Jul. 14, 2025

Mountain goats deal with heavy snow, and have a short window of time to fatten up before the thick of winter.

From Seattle Times • May 22, 2024

She felt slightly guilty because she had just stolen a pot of the millet-and-honey cakes Aunt Chipo kept to fatten her daughter up.

From "A Girl Named Disaster" by Nancy Farmer

Related Words

• augment
• broaden
• build up
• swell