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.

---

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

---

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

Soybean Export Council, a trade group, opened a Beijing office in 1982 to spread the word about protein-packed U.S. soybeans used to fatten livestock.

From The Wall Street Journal • Nov. 7, 2025

The Seahawks need to fatten up before staring down this quartet of stiff challenges: 49ers, Cowboys, 49ers, Eagles.

From Seattle Times • Nov. 17, 2023

Liz Truss told the Institute for Government she tried to rear, fatten and slaughter a pig on market day in her rush to meet voters' need for change saying she had "limited time".

From BBC • Sep. 18, 2023

“That gives the larvae a chance to fatten up nicely, the way the hens like them, but not quite long enough to hatch into flies.”

From "The Omnivore's Dilemma" by Michael Pollan

Related Words

• augment
• broaden
• build up
• swell