Fat

UK: /ˈfæt/ US: /fæt/ ,(fat)

Inflections of 'fat' (adj):

fatter

adj comparative

fattest

adj superlative

Inflections of 'fat' (v): (⇒ conjugate)

fats

v 3rd person singular

fatting

v pres p

fatted

v past

fatted

v past p

WordReference Random House Learner's Dictionary of American English © 2026

fat /fæt/   n., adj., fat•ter, fat•test. 
n. 

1. Anatomy an oily substance found in certain animal tissue and plant seeds, and used in cooking and in the manufacture of soaps and other products:
   [uncountable] His diet was too rich in fat.
   [countable] Different fats are used in the preparation of this cooking oil.
2. Anatomy animal tissue containing much of this substance:
   [uncountable] to have rolls of fat around one's waist.
3. the richest or best part of anything:
   [uncountable] the fat of the land.

adj. 

4. having too much fat;
   corpulent:
   a fat person.
5. plump;
   well-fed:
   a fat chicken.
6. made up of or containing fat;
   greasy;
   oily;
   fatty:
   fat meat.
7. profitable;
   providing a lot of money;
   lucrative:
   a fat job in government.

Idioms

8. fat chance, a very slight chance;
   small probability:
   A fat chance we have of getting a raise!
9. Idioms the fat is in the fire, something has been done or started that cannot be reversed and will probably have dramatic or serious consequences:
   Now that the enemy has begun its invasion, the fat is in the fire.

fat•ness, n. [uncountable] ]
Related Words

fat is a noun and an adjective, fatness is a noun, fatten is a verb:
The meat has too much fat in it. You're too fat; you need to go on a diet. Unfortunately, fatness is bad for your health. The farmer wanted to fatten his pigs.

WordReference Random House Unabridged Dictionary of American English © 2026

fat  (fat), adj., fat•ter, fat•test, n., v., fat•ted, fat•ting. 
adj. 

1. having too much flabby tissue;
   corpulent;
   obese:
   a fat person.
2. plump;
   well-fed:
   a good, fat chicken.
3. consisting of or containing fat;
   greasy;
   oily:
   fat gravy; fat meat.
4. profitable, as an office:
   a fat job on the city commission.
5. affording good opportunities, esp. for gain:
   a fat business contract.
6. wealthy;
   prosperous;
   rich:
   He grew fat on dishonest profits.
7. big, broad, or extended;
   thick:
   a fat sheaf of bills.
8. plentiful;
   abundant:
   a fat supply of food.
9. plentifully supplied:
   a fat larder; a fat feast.
10. dull;
    stupid:
    fat clumsiness of manner.
11. abounding in a particular element:
    Fat pine is rich in resin.
12. (of paint) having more oil than pigment. Cf. lean² (def. 6).
13. Mining (of coal) highly bituminous;
    rich in volatile hydrocarbons.
14. Ceramics long¹ (def. 25).
15. fertile, as land:
    Everything grows in this fat soil.
16. a fat chance, [Slang.] a very slight chance;
    small probability:
    A fat chance he has of winning the title!
17. Slang Terms a fat lot, little or not at all:
    A fat lot they care about anyone else's troubles!

n. 

18. Anatomy any of several white or yellowish greasy substances, forming the chief part of adipose tissue of animals and also occurring in plants, that when pure are colorless, odorless, and tasteless and are either solid or liquid esters of glycerol with fatty acids;
    fats are insoluble in water or cold alcohol but soluble in ether, chloroform, or benzene: used in the manufacture of soap, paints, and other protective coatings and in cooking.
19. Anatomy animal tissue containing much of this substance;
    loose flesh;
    flabbiness:
    to have rolls of fat around one's waist.
20. the richest or best part of anything.
21. obesity;
    corpulence:
    In his later years, he inclined to fat.
22. Slang Terms especially profitable or advantageous work.
23. an overabundance or excess;
    superfluity.
24. action or lines in a dramatic part that permit an actor to display abilities.
25. Printing Also, phat. Also called lift. [Typesetting.] matter that can be composed easily and profitably, esp. from standing type, illustrations, or the like:
    fat work.
    Cf. lean² (def. 11).
26. Idioms chew the fat. See chew (def. 9).
27. Idioms the fat is in the fire:
    • an irrevocable action or chain of events has been started;
      the die is cast:
      Now that they have been given an ultimatum, the fat is in the fire.
    • the decision, whether good or bad, has been made.
    • the crisis is imminent.
28. Idioms the fat of the land, the best or richest of anything obtainable:
    to live on the fat of the land.

v.t., v.i. 

29. to make or become fat.

• bef. 1000; Middle English; Old English fǣtt, origin, originally past participle of fǣtan to cram, load, adorn; cognate with Gothic fētjan to adorn; akin to vat

fat′less, adj. 
fat′like′, adj. 
Synonyms

• 1. portly, adipose, pudgy. See stout. 
• 3. unctuous, fatty.
• 4. lucrative, remunerative.
• 8. copious.
• 10. sluggish.
• 15. rich, fruitful, productive.

Antonyms

• 1. thin.
• 3. lean.
• 10. clever.
• 15. sterile, barren.

Collins Concise English Dictionary © HarperCollins Publishers::

fat / fæt/ noun

1. any of a class of naturally occurring soft greasy solids that are esters of glycerol and certain fatty acids. They are present in some plants and in the adipose tissue of animals, forming a reserve energy source, and are used in making soap and paint and in the food industry
   See also oil1
2. vegetable or animal tissue containing fat
3. corpulence, obesity, or plumpness
4. the best or richest part of something
5. the fat is in the fire ⇒ an irrevocable action has been taken, esp one from which dire consequences are expected
6. the fat of the land ⇒ the best that is obtainable

adjective (fatter, fattest)

1. having much or too much flesh or fat
2. consisting of or containing fat; greasy: fat pork
3. profitable; lucrative
4. affording great opportunities: a fat part in the play
5. fertile or productive: a fat land
6. thick, broad, or extended: a fat log of wood
7. very little or none; minimal (in phrases such as a fat chance, a fat lot of good, etc)

verb (fats, fatting, fatted)

1. to make or become fat; fatten

Etymology: Old English fǣtt, past participle of fǣtan to cram; related to Old Norse feita, Old High German feizen to fatten; compare Gothic fētjan to adorn

ˈfatless adjective

ˈfatly adverb

ˈfatness noun

ˈfattish adjective