fat (f²t) n. 1.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. 3. The best or richest part: living off the fat of the land. 4. Unnecessary excess: “would drain the appropriation's fat without cutting into education's muscle” (New York Times). --fat 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. 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. 6.a. Yielding profit or plenty; lucrative or rewarding: a fat promotion. b. Prosperous; wealthy: grew fat on illegal profits. 7.a. Thick; large: a fat book. b. Puffed up; swollen: a fat lip. --fat tr. & intr.v. fat·ted, fat·ting, fats. To make or become fat; fatten. --idioms. 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. [Middle English, from Old English fÆtt. See pei…- below.] --fat“ly adv. --fat“ness n.
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SYNONYMS: fat, obese, corpulent, fleshy, portly, stout, pudgy, rotund, plump, chubby. These adjectives mean having an abundance and often an excess of flesh. Fat implies excessive weight and is generally unfavorable in its connotations: not merely overweight but downright fat. Obese and corpulent imply gross overweight: “a woman of robust frame . . . though stout, not obese” (Charlotte Brontë). Her father is too corpulent to play handball. Fleshy implies a not necessarily excessive abundance of flesh: firm, fleshy arms. Portly and stout are sometimes used as polite terms to describe fatness. In stricter application portly refers to a person whose bulk is combined with a stately or imposing bearing, and stout, to a person with a thickset, bulky figure: “a portly, rubicund man of middle age” (Winston Churchill). Even slim girls can become stout matrons. Pudgy means short and fat: pudgy fingers. Rotund suggests roundness of figure, often in a squat person: “this pink-faced rotund specimen of prosperity” (George Eliot). Plump applies to a pleasing fullness of figure: a plump, rosy little girl. A chubby person is round and plump: a chubby toddler; chubby cheeks.
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 pei…-. Important derivatives are: fat, pituitary, pine1, Irish.
pei…-. To be fat, swell. 1. Extended o-grade form *poid-. FAT, from Old English fÆt(t), fat, from Germanic past participle *faitidaz, fattened, from derivative verb *faitjan, to fatten, from *faitaz, plump, fat. 2. Possibly suffixed zero-grade form *pº-tu-. PIP5, PITUITARY, from Latin pºtuºta, moisture exuded from trees, gum, phlegm. 3. Possibly suffixed zero-grade form *pº-nu-. PINE1, PINEAL, PINNACE, PIñON, PINOT; PIñA CLOTH, from Latin pºnus, pine tree (yielding a resin). 4. Suffixed zero-grade form *pº-won-. PROPIONIC ACID, from Greek pi½n, fat. 5. Suffixed zero-grade form *pº-wer-, “fat, fertile.” a. (ERSE), IRISH, from Old English Þras, the Irish, from *Þwer-i¿, the prehistoric Celtic name for Ireland; b. PIERIAN SPRING, from Greek Pieria, a region of Macedonia, from *Pºwer-i³. [Pokorny peð(…)- 793.]