thin
Americanadjective
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having relatively little extent from one surface or side to the opposite; not thick.
thin ice.
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of small cross section in comparison with the length; slender.
a thin wire.
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having little flesh; spare; lean.
a thin man.
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composed of or containing objects, particles, etc., widely separated; sparse.
thin vegetation.
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scant; not abundant or plentiful.
- Synonyms:
- meager
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of relatively slight consistency or viscosity.
thin soup.
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rarefied, as air.
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without solidity or substance; flimsy.
a very thin plot for such a long book.
- Synonyms:
- weak
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lacking fullness or volume; weak and shrill.
a thin voice.
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without force or a sincere effort.
a thin smile.
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lacking body, richness, or strength.
a thin wine.
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lacking in chroma; of light tint.
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Photography. (of a developed negative) lacking in density or contrast through underdevelopment or underexposure.
adverb
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in a thin manner.
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sparsely; not densely.
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so as to produce something thin.
Slice the ham thin.
verb (used with object)
verb (used without object)
adjective
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of relatively small extent from one side or surface to the other; fine or narrow
-
slim or lean
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sparsely placed; meagre
thin hair
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of relatively low density or viscosity
a thin liquid
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weak; poor; insufficient
a thin disguise
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(of a photographic negative) having low density, usually insufficient to produce a satisfactory positive
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mountaineering a climb or pitch on which the holds are few and small
-
few in number; scarce
adverb
verb
Synonym Usage
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
Derived Forms
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overthinnessnoun
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thinnessnoun
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overthinadjective
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self-thinningadjective
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superthinadjective
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unthinnedadjective
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unthinningadjective
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overthinlyadverb
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thinlyadverb
Inflected Forms
Participles
Conjugated Forms
Present
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thinsimple
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thinssimple
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have thinnedperfect
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has thinnedperfect
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am thinningprogressive
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are thinningprogressive
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is thinningprogressive
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have been thinningperfect progressive
-
has been thinningperfect progressive
Past
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thinnedsimple
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had thinnedperfect
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was thinningprogressive
-
were thinningprogressive
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had been thinningperfect progressive
Future
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.
Vocabulary lists containing thin
The SAT: Multiple-Meaning Words, List 4
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The New SAT: Multiple-Meaning Words
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
The ACT Reading Test: Multiple-Meaning Words, List 4
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
These decisions clearly suggest that long-standing, anti-unitarian landmark decisions such as Humphrey’s were on thin ice.
From Salon • Jul. 1, 2026
The line between giving just enough personal information for a better prompt, and dangerous oversharing, can be thin when you’re interacting with a chatbot.
From MarketWatch • Jul. 1, 2026
The paper calls it the "Burnham bounce", but warns that the margin between both parties is "wafer thin".
From BBC • Jun. 26, 2026
Longer potatoes with a thin skin that makes them easier to peel, and varieties that crisp up when cooked to produce that perfect fluffy fry, were just a few of the company’s criteria.
From The Wall Street Journal • Jun. 23, 2026
Her grip on my knee stiffens and her mouth freezes into a thin line.
From "Red Flags and Butterflies" by Sheryl Azzam
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
