a. The ester of glycerol and one, two, or three fatty acids.
b. Any of various soft, solid, or semisolid organic compounds constituting the esters of glycerol and fatty acids and their associated organic groups.
c. A mixture of such compounds occurring widely in organic tissue, especially in the adipose tissue of animals and in the seeds, nuts, and fruits of plants.
d. Animal tissue containing such substances.
e. A solidified animal or vegetable oil.
2. Obesity; corpulence: health risks associated with fat.
3. Unnecessary excess: "would drain the appropriation's fat without cutting into education's muscle" (New York Times).
adj. fat·ter, fat·test
1. Having much or too much fat or flesh; plump or obese.
2. Full of fat or oil; greasy.
3. Abounding in desirable elements: a paycheck fat with bonus money.
4. Fertile or productive; rich: "It was a fine, green, fat landscape" (Robert Louis Stevenson).
5. Having an abundance or amplitude; well-stocked: a fat larder.
a. Yielding profit or plenty; lucrative or rewarding: a fat promotion.
b. Prosperous; wealthy: grew fat on illegal profits.
a. Thick; large: a fat book.
b. Puffed up; swollen: a fat lip.
tr. & intr.v. fat·ted, fat·ting, fatsIdioms:
To make or become fat; fatten.
a fat lot Slang
Very little or none at all: a fat lot of good it will do him.
fat chance Slang
Very little or no chance.
the fat is in the fire
Bad consequences are sure to follow; trouble lies ahead.
the fat of the land
Desirable resources, especially when acquired with little effort: I fantasized about buying a farm and living off the fat of the land.
[Middle English, from Old English fǣtt, fatted; see peiə- in the Appendix of Indo-European roots.]
Synonyms: fat, overweight, obese, corpulent, portly, stout, pudgy, rotund, plump1, chubby
These adjectives mean having an abundance and often an excess of flesh. Fat implies more weight than one desires or than is considered desirable by social norms: was getting fat and decided to exercise. Overweight conveys the sense that the weight is above a medical standard for age or height and may be unhealthy: oversized garments for overweight customers. Another word with medical connotations, obese means grossly overweight: "a woman of robust frame ... though stout, not obese" (Charlotte Brontë).
While corpulent also refers to conspicuous body weight, it is not always as judgmental a term as obese: the corpulent figure of the seated Buddha. Portly refers to bulk combined with a stately or imposing bearing: A portly guard blocked the doorway. Stout denotes a thickset, bulky figure: a painting of stout peasants. Pudgy means short and fat: pudgy fingers. Rotund refers to the roundness of figure associated with a spreading midsection: "this pink-faced rotund specimen of prosperity" (George Eliot).
Plump and chubby apply to a pleasing fullness of figure: a plump little toddler; chubby cheeks.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.