thin

Formsthinner, thinnest

Formsthins, thinning, thinned

Pluralthins

1. 1
   adjective

   Having little thickness or width; having opposite surfaces or sides close together, as of a slice, a wall, a wire, or a line.

   The walls were so thin that we could hear every conversation next door.

   A thin layer of dust covered the old books on the top shelf.

   UsageRoads, rivers and doorways are usually narrow; thin suits slices, walls, wires and lines.

   Similarfine, narrow, slender

   Oppositethick, wide

2. 2
   not fatadjective

   Lean or slender in build, lacking much fat or flesh, sometimes to the point of gauntness.

   Years of hard labor had left her arms thin and wiry.

   The runners were lean and thin after months of training.

   UsageSlim is the more flattering word and skinny the more casual, often critical one; thin sits between them.

   Similarslim, slender, lean, skinny, slight

   Oppositefat, plump, stout, overweight

3. 3
   adjective

   Scarce or sparse; not dense, crowded, or numerous, as of hair, a crowd, an audience, or traffic on a route.

   Attendance was thin on the rainy weekday afternoon.

   The grass was thin and patchy across the dry field.

   UsageSet phrases: thin on the ground, meaning scarce, and thin on top, meaning losing hair.

   Similarsparse, scanty, meager, light

   Oppositedense, thick, heavy

   Note

   An older construction survives in this sense: thin of plus a noun, meaning sparsely supplied with it. Joseph Addison's Remarks on Several Parts of Italy (1705) finds Ferrara "very large, but extremely thin of people." Source

   Checked 2 Nov 2026 · 4 facts

   • The older construction thin of plus a noun could describe a sparse supply of something. archive.org
   • Joseph Addison wrote Remarks on Several Parts of Italy, first published in 1705. openlibrary.org
   • The first edition dates from 1705. archive.org
   • Addison describes Ferrara using the quoted words. archive.org
4. 4
   become less thickverbintransitive

   To become thinner, sparser, or less dense over time.

   The crowd thinned quickly once the music stopped.

   Toward dawn the clouds thin and break apart over the hills.

   UsageOften thin out: the crowd thinned out. Thinning hair is becoming less dense.

   Similardisperse, dwindle, dissipate, scatter, diminish

   Oppositethicken, swell

5. 5
   adjective

   Slight, flimsy, or superficial; inadequate, and not enough to cover or convince.

   The whole defense rested on a thin set of facts.

   The report's conclusions seemed thin once you saw how little data supported them.

   UsageCommon with excuses and evidence: a thin excuse. Something that wears thin stops being convincing or amusing.

   Similarflimsy, tenuous, weak, slight, feeble

   Oppositesolid, strong, substantial, convincing

   Note

   Here the physical sense turns figurative. A disguise is thin when it can be seen through, an idea that the "little thickness" sense already hints at with a veil "thinnest and most transparent." The word suits anything offered as cover or proof that fails to hide or convince: a disguise, an excuse, a case resting on too few facts. Source

   Checked 1 Nov 2026 · 1 fact

   • The quoted wording describes a veil in the example listed under the little-thickness sense. en.wiktionary.org
6. 6
   adjective

   Lacking body, volume, or strength; feeble, faint, or not full.

   His thin tenor barely carried across the crowded hall.

   A thin, watery light came through the clouds in the late afternoon.

   Similarweak, feeble, faint, watery, reedy

   Oppositerich, full, strong, robust

7. 7
   adjective

   Of a liquid, having low viscosity; runny and flowing easily rather than thick.

   The oil was thin enough to seep through the tiny cracks.

   A thin broth simmered gently on the back of the stove.

   Similarrunny, watery, fluid

   Oppositethick, viscous

   Note

   Two physical properties share the word here. Thin can mean runny, as water is thinner than honey, but it also covers low specific gravity: a fluid that is light for its volume rather than quick to pour. Everyday speech leans on the runny meaning. A specialist may mean either, so context has to settle which one is meant. Source

   Checked 1 Nov 2026 · 4 facts

   • Thin can describe either low viscosity or low specific gravity. en.wiktionary.org
   • Water is thinner than honey. en.wiktionary.org
   • Specific gravity concerns relative density. ttb.gov
   • Being light for its volume means having low density. starchild.gsfc.nasa.gov
8. 8
   verbtransitive

   To make something less thick, especially to make a liquid runnier or weaker by adding water or another fluid.

   Bakers thin the batter until it pours smoothly from the jug.

   The carpenter thinned the edge of the door with a plane so it would close properly.

   UsageOften thin a liquid with water or milk, or thin it down.

   Similardilute, weaken, pare

   Oppositethicken, concentrate

   Note

   The object can be a liquid, a layer, or even blood. Theodore Roethke's poem "Feud," in Open House (1941), uses it of exhausted fathers and the blood they pass on, a line about weakness handed down through a family.

9. 9
   remove plantsverbtransitive

   To remove some of the plants, shoots, flowers, or young fruits in a group so that those remaining have more space and grow better.

   Orchard workers thin the young apples to produce larger fruit at harvest.

   Thin the lettuce rows once the first sprouts appear.

   UsageCommon patterns include thin the carrots, thin out the seedlings, and thin the carrots to four inches apart.

   Note

   Mark Diacono, writing in The Daily Telegraph in 2015, recommends thinning young Asian pears so the tree is not overburdened, though he cannot quite bring himself to thin the flowers. Source

   Checked 2 Nov 2026 · 3 facts

   • Mark Diacono wrote the cited passage in The Daily Telegraph in 2015; Wiktionary identifies the article as "In praise of the Asian pear," dated 5 September 2015. en.wiktionary.org
   • Diacono recommends thinning young Asian pears to avoid overburdening the tree. en.wiktionary.org
   • Diacono says he cannot quite bring himself to thin the flowers. en.wiktionary.org

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