fat

1 of 3

adjective

ˈfat 

fatter; fattest

1

: notable for having an unusual amount of fat:

a

: plump

a cute, fat little baby

b

: having excessive body fat

… a woman of medium height, a little plump but not fat …

—Mary McCarthy

c

of a meat animal : fattened for market

d

of food : oily, greasy

a fat, rich cheese

2

a

: well filled out : thick, big

a fat book

b

: full in tone and quality : rich

… a gorgeous fat bass voice …

—Irish Digest

c

: well stocked

a fat larder

d

: prosperous, wealthy

The company grew fat on profits during the war.

e

: being substantial and impressive

a fat bank account

3

a

: richly rewarding or profitable

a fat part in a movie

a fat contract

b

: practically nonexistent

a fat chance

4

: productive, fertile

a fat year for crops

5

informal : stupid, foolish

"… if he had had any sense in his fat head, he would have done it long ago, dash him!"

—P. G. Wodehouse

6

: being swollen

got a fat lip from the fight

7

of a baseball pitch : easy to hit

fatness noun

fat

2 of 3

verb

fatted; fatting

transitive verb

: to make fat : fatten

fat

3 of 3

noun

1

: animal tissue consisting chiefly of cells distended with greasy or oily matter

2

a

: oily or greasy matter making up the bulk of adipose tissue and often abundant in seeds

b

: any of various compounds of carbon, hydrogen, and oxygen that are glycerides of fatty acids, are the chief constituents of plant and animal fat, are a major class of energy-rich food, and are soluble in organic solvents but not in water

c

: a solid or semisolid fat as distinguished from an oil

3

: the best or richest part

4

: obesity

5

: something in excess : superfluity

… trim the fat from the news operation …

—Ray Olson

fatless

ˈfat-ləs 

adjective

Synonyms of fat

Adjective

• plump
• round
• obese

Noun

• best
• aristocracy
• cream
• pink
• elite
• top
• elect
• flower
• royalty
• priesthood
• prime
• Hall of Fame
• society
• choice

Examples of fat in a Sentence

Adjective

The dog is getting fat because you feed him too much.

I can't believe I've let myself get so fat.

a fat book of poems

a truck with fat tires

Noun

people with excess body fat

a diet and exercise program to help you gain muscle and lose fat

Nuts contain a lot of fat.

Trim the fat from the meat before you cook it.

a diet low in fats

fats like butter and olive oil

trim the fat off the budget

Recent Examples on the Web

Adjective

Vitamin D for Strong Bones Vitamin D is a fat-soluble vitamin. —T'keyah Bazin, Verywell Health, 5 Nov. 2025

Being fat or an immigrant or full of self-pity for one reason or other. —Literary Hub, 4 Nov. 2025

Noun

Animal and infant studies published in Nutrition Research Reviews suggest that the way these fats are structured can affect how the body digests them and processes cholesterol, while adult studies have shown inconsistent results that appear to depend on the type of fat and how much people consume. —Deirdre Bardolf, FOXNews.com, 7 Nov. 2025

This eating plan focuses on foods with a variety of nutrients such as green leafy vegetables, fish and whole grains that are beneficial for cognitive function and don’t include ones with high amounts of trans and saturated fats. —Jocelyn Solis-Moreira, Flow Space, 7 Nov. 2025

Word History

Etymology

Adjective, Verb, and Noun

Middle English, from Old English fǣtt, past participle of fǣtan to cram; akin to Old High German feizit fat

First Known Use

Adjective

before the 12th century, in the meaning defined at sense 1

Verb

14th century, in the meaning defined above

Noun

14th century, in the meaning defined at sense 1

Phrases Containing fat

• a (fat) lot of good
• baby fat
• big fat
• brown fat
• burn fat
• chew the fat
• deep fat
• deep-fat fryer
• fat body
• fat-burning
• fat cat
• fat cell
• fat city
• fat depot
• fat farm
• fat-free
• fat-shame
• fat shamer
• fat shaming
• fat-tailed sheep
• fat-witted
• full-fat
• it ain't over until/till the fat lady sings
• leaf fat
• live off/on the fat of the land
• low-fat
• milk fat
• monounsaturated fat
• polyunsaturated fat
• puppy fat
• saturated fat
• trans-fat
• unsaturated fat
• wool fat

Rhymes for fat

• at
• bat
• batt
• brat
• cat
• chat
• flat
• gat
• gnat
• hat
• kat
• mat

Kids Definition

fat

1 of 3 adjective

ˈfat 

fatter; fattest

1

a

: plump entry 5, fleshy

b

: oily sense 1, greasy

2

a

: thick entry 1 sense 1

a fat book

b

: well stocked : abundant

3

: profitable

accepted a fat contract

4

: productive sense 1, fertile

5

: being swollen

got a fat lip in the fight

fatness noun

fat

2 of 3 verb

fatted; fatting

: to make fat : fatten

fat

3 of 3 noun

1

: animal tissue consisting chiefly of cells containing much greasy or oily matter

2

a

: any of numerous compounds of carbon, hydrogen, and oxygen that make up most of plant and animal fat, are a major class of energy-rich food, and can be dissolved by ether but not by water

b

: a solid or semisolid fat (as lard) as distinguished from an oil

3

: the best or richest part

the fat of the land

4

: an amount beyond what is usual or needed : excess

Medical Definition

fat

1 of 2 adjective

ˈfat 

fatter; fattest

: notable for having an unusual amount of fat

especially : fleshy with superfluous flabby tissue that is not muscle : obese

fatness noun

fat

2 of 2 noun

1

: animal tissue consisting chiefly of cells distended with greasy or oily matter see brown fat

2

a

: oily or greasy matter making up the bulk of adipose tissue

b

: any of numerous compounds of carbon, hydrogen, and oxygen that are glycerides of fatty acids, are the chief constituents of plant and animal fat, are a major class of energy-rich food, and are soluble in organic solvents (as ether) but not in water

c

: a solid or semisolid fat as distinguished from an oil

3

: the condition of fatness : obesity