thin

American  

[thin] / θɪn /

adjective

thinner, thinnest

1. having relatively little extent from one surface or side to the opposite; not thick.

   thin ice.

2. of small cross section in comparison with the length; slender.

   a thin wire.

3. having little flesh; spare; lean.

   a thin man.

   Synonyms:

   scrawny, lank, skinny, slender, slim

4. composed of or containing objects, particles, etc., widely separated; sparse.

   thin vegetation.

5. scant; not abundant or plentiful.

   Synonyms:

   meager

6. of relatively slight consistency or viscosity.

   thin soup.

7. rarefied, as air.

8. without solidity or substance; flimsy.

   a very thin plot for such a long book.

   Synonyms:

   weak

9. lacking fullness or volume; weak and shrill.

   a thin voice.

10. without force or a sincere effort.

    a thin smile.

11. lacking body, richness, or strength.

    a thin wine.

12. lacking in chroma; of light tint.

13. Photography. (of a developed negative) lacking in density or contrast through underdevelopment or underexposure.

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adverb

1. in a thin manner.

2. sparsely; not densely.

3. so as to produce something thin.

   Slice the ham thin.

verb (used with object)

thinned, thinning

1. to make thin or thinner (often followed by down, out, etc.).

verb (used without object)

thinned, thinning

1. to become thin or thinner; become reduced or diminished (often followed by down, out, off, etc.).

   The crowd is thinning out.

thin British  

/ θɪn /

adjective

1. of relatively small extent from one side or surface to the other; fine or narrow

2. slim or lean

3. sparsely placed; meagre

   thin hair

4. of relatively low density or viscosity

   a thin liquid

5. weak; poor; insufficient

   a thin disguise

6. (of a photographic negative) having low density, usually insufficient to produce a satisfactory positive

7. mountaineering a climb or pitch on which the holds are few and small

8. few in number; scarce

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adverb

1. in order to produce something thin

   to cut bread thin

verb

1. to make or become thin or sparse

thin Idioms  

More idioms and phrases containing thin

• into thin air
• on thin ice
• spread oneself too thin
• through thick and thin
• wear thin

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Related Words

Thin, gaunt, lean, spare agree in referring to one having little flesh. Thin applies often to one in an unnaturally reduced state, as from sickness, overwork, lack of food, or the like: a thin, dirty little waif. Gaunt suggests the angularity of bones prominently displayed in a thin face and body: to look ill and gaunt. Lean usually applies to a person or animal that is naturally thin: looking lean but healthy after an outdoor vacation. Spare implies a muscular leanness with no diminution of vitality: Lincoln was spare in body.

Other Word Forms

• overthin adjective
• overthinly adverb
• overthinness noun
• self-thinning adjective
• superthin adjective
• thinly adverb
• thinness noun
• unthinned adjective
• unthinning adjective

Etymology

Origin of thin

First recorded before 900; (adjective and adverb) Middle English thyn(ne), Old English thynne; cognate with Dutch dun, German dünn, Old Norse thunnr; (verb) Middle English thynnen, Old English thynnian, derivative of the adjective; compare Middle Dutch dunnen, Old Norse thynna; akin to Old Irish tana, Latin tenuis thin, Greek tany- long

Explanation

Something thin is narrow or not very thick. If you wear thin socks on a cold winter day, your toes might start to feel numb. Thin can describe something that is narrow and slender, like a hair or a thread. It can also describe a layer of something that is not very thick, such as paper. To thin something out is to make it lesser or weaker, like thinning out a sauce by adding water. You can also use this word figuratively. An argument that is not very convincing is thin.

Example Sentences

Shares in American Airlines jumped 4% premarket, while United shares rose in thin premarket trading.

From The Wall Street Journal • Apr. 14, 2026

He guides me inside a warehouse full of vast, bubbling water tanks and heaves out a haul of the squirming, long, thin black fish.

From BBC • Apr. 12, 2026

In the years since, I’ve kept one eye open in case any new “Cloverfield” properties drop out of thin air.

From Salon • Apr. 12, 2026

Scientists often had to slice brain tissue into extremely thin sections, image them with microscopes and piece together the pathways manually.

From Science Daily • Apr. 7, 2026

But, as you can imagine, when he tried to add some raspberries onto the second long, thin icicle pop that he grabbed, they all quickly slid off.

From "The Very, Very Far North" by Dan Bar-el

Related Words

• delicate
• fragile
• gaunt
• lean
• meager
• narrow
• skinny
• slim
• small