thin
thin — verb
- thinpresent simple I / you / we / they
- thins3rd person singular
- thinning-ing form
- thinnedpast simple
1. to add water or another liquid to a thick substance so that it becomes less thic
to add water or another liquid to a thick substance so that it becomes less thick and flows more easily
Talia thinned the dark paint with water before brushing it onto the wall.
transitive: thin + noun + with + noun (liquid agent)
The gravy was too thick, so Diya thinned it with a little milk.
passive: 'was thinned'; 'by -ing' clause for method
If the paste feels too stiff for the paper, thin it slowly with warm water.
Sana thins her oil paints with a blending medium, then builds up soft layers of colour on the canvas.
As Noa brushed the wood glue onto the joint, it thinned quickly and soaked deep into the grain.
- dilute
more formal or scientific; used in chemistry and cooking
- water down
informal; often implies making something weaker or less acceptable
- weaken
focuses on reduced strength or concentration rather than consistency
- thicken
the opposite action; to make a substance more thick and less liquid
文法句型
thin + noun + with/by + noun (transitive)
thin + adverb/prepositional phrase (intransitive)
用法筆記
This sense can be transitive (thin + object) or intransitive (the substance thins on its own). The liquid agent is introduced with 'with' or 'by -ing'. Intransitive uses are less common and usually describe a natural process (e.g., paint thins as it warms).
常見錯誤
2. to become smaller in number, or to remove some items from a group so that the re
to become smaller in number, or to remove some items from a group so that the remaining items have more room to grow or exist
The crowd outside the theatre thinned quickly after the final curtain came down.
intransitive: crowd + thins
Putri thinned out the carrot seedlings so the strongest plants would have room to grow.
transitive: thin + out + noun (gardening)
As midnight approached, the number of guests at the party began to thin noticeably.
The gardener thinned the lettuce rows to give each head enough space and sunlight.
Traffic on the highway usually thins out after the evening rush hour ends.
文法句型
thin (out) (intransitive) — subject is a crowd/group
thin + noun + out (transitive) — object is plants/seedlings/crowd
用法筆記
Frequently used with 'out', especially in conversation. The intransitive use describes crowds, traffic, hair, or any group becoming less dense. The transitive use is common in gardening and forestry, where a gardener removes some plants so the rest have more room.
常見錯誤
thin — adjective
- thinpositive
- thinnercomparative
- thinnestsuperlative
1. measuring very little from one flat side to the other, so that something is not
measuring very little from one flat side to the other, so that something is not thick — for instance, a slice of bread, a layer of paint, or a wall.
The ice on the pond was too thin for anyone to walk on.
predicative use with too
Jabari cut the cheese into thin slices for the sandwiches.
attributive: thin + noun (slices)
A thin layer of dust covered every surface in the old library.
The walls in Andrei's apartment were so thin that he could hear his neighbours arguing.
文法句型
thin + noun (attributive)
be + thin (predicative)
用法筆記
Gradable adjective: you can say thinner, thinnest, very thin, too thin.
常見錯誤
2. having a body with very little fat or muscle so that the shape of the bones can
having a body with very little fat or muscle so that the shape of the bones can often be seen.
Heloísa was tall and thin, with long legs like a dancer.
predicative: be + thin describing a person
After the long illness, the old man's thin face showed every bone.
attributive: thin + body part (face)
Putri wrapped her thin arms around her knees in the hospital waiting room, staring at the floor.
The stray cat was dangerously thin, with its ribs clearly visible through its fur.
文法句型
be + thin (describing body)
thin + noun (body part)
用法筆記
Can describe both positive slimness and concerning thinness depending on modifiers (e.g. 'pleasantly thin' vs 'dangerously thin').
常見錯誤
3. reduced to a very thin state by continuous use, pressure, or the passage of time
reduced to a very thin state by continuous use, pressure, or the passage of time so that the material is weak or nearly gone.
The soles of Cyrus's shoes had worn thin after months of hiking on rocky trails.
pattern: wear + thin (become thin from use)
The knees of Minho's jeans became thin after two years of daily wear.
The old woollen blanket was so thin that light passed right through the faded fabric.
Hugo's favourite cotton shirt grew thin at the collar from years of washing.
- threadbare
specifically for fabric or cloth that has worn thin
- worn
focuses on damage from use, not necessarily thinness
文法句型
wear + thin
grow + thin
become + thin
用法筆記
Often appears with verbs like 'wear' and 'grow' to describe gradual thinning from use or age. Distinguish from sense 1 (NOT THICK), which describes a permanent physical property; sense 3 describes a change over time.
4. so fine or delicate that light passes through or objects on the other side can b
so fine or delicate that light passes through or objects on the other side can be partly seen.
The curtains were so thin that sunlight filled the room every morning.
pattern: so thin that... (result clause)
Imran could see the outline of the tree through the thin paper of the envelope.
Tamar wore a thin silk scarf that seemed almost see-through in the bright light.
The thin cotton of his shirt showed the tattoo on his shoulder underneath.
- sheer
technical term for very thin fabric you can see through
- translucent
formal; lets light through but not clear images
- transparent
you can see clearly through; stronger than thin
文法句型
thin + noun (fabric/material)
so thin that...
5. present in a smaller number or amount than usual or expected; not plentiful.
present in a smaller number or amount than usual or expected; not plentiful.
The audience was thin on the rainy Tuesday evening.
predicative: be + thin describing crowd size
Job openings were thin in the small village where Eli grew up.
Traffic on the highway was thin late at night, making the drive peaceful.
Padma noticed that the crowd was thin at the early morning yoga class.
文法句型
be + thin (for amounts/crowds)
thin on the ground
用法筆記
Usually used predicatively (e.g. 'the crowd was thin'). Less common attributively (e.g. 'thin attendance'). Often describes people, traffic, opportunities, or evidence.
常見錯誤
6. of air at high altitudes, where the amount of available oxygen is far lower than
of air at high altitudes, where the amount of available oxygen is far lower than what people are used to at sea level.
The air grew thin as the climbers approached the top of the mountain.
pattern: air + grow/become + thin (gradual change)
Hikers on the high plateau found the thin air made breathing difficult.
attributive: thin air
Christopher felt dizzy in the thin air of the high-altitude city.
Pilots receive special training for dealing with the effects of thin air.
文法句型
thin + air
the air is + thin
用法筆記
Almost exclusively used with the word 'air'. Not used for other gases or liquids in this sense.
常見錯誤
7. Having a high proportion of water or another agent so that a liquid flows and po
Having a high proportion of water or another agent so that a liquid flows and pours easily rather than being thick or sticky — used of sauce, soup, paint, oil, and similar substances.
The sauce was too thin, so Chef Dario added cornstarch to thicken it.
opposite: thicken
After boiling, the soup becomes thin and watery, perfect for a light meal.
collocation: thin and watery
Saira prefers her paint thin so it spreads smoothly across the canvas.
A thin oil flows through the engine faster than a thick one.
The medicine is a thin liquid that you drink from a small plastic spoon.
用法筆記
Frequently paired with thick as an antonym pair; the opposite of thinning a liquid is thickening it.
常見錯誤
8. Lacking strength, substance, or quality — used when a sound does not sound full,
Lacking strength, substance, or quality — used when a sound does not sound full, an excuse or argument is not convincing, support is not sincere, or something is of poor overall quality.
Christopher offered a thin excuse for being late — a stray goat had blocked his driveway — and no one believed him.
collocation: thin excuse = unconvincing
Aoi's voice sounded thin and shaky during the outdoor concert, barely reaching the audience in the back rows.
collocation: thin voice = weak, lacking fullness
The film's plot was too thin to hold the audience for two hours.
Yael gave a thin smile when she heard the news, hiding her true feelings.
Rachid's argument was so thin that the judge dismissed it immediately.
- strong
direct opposite across all contexts
- convincing
specific to arguments and excuses
- rich
for sounds, voices, or materials that are full and resonant
用法筆記
Most commonly used with nouns like excuse, voice, smile, argument, plot, and material. The meaning varies slightly by noun: thin excuse = easy to disprove; thin voice = high and lacking resonance; thin smile = forced or insincere.
常見錯誤
9. Growing or arranged with wide gaps between individual items rather than being pa
Growing or arranged with wide gaps between individual items rather than being packed close together — used of hair, fur, grass, or other vegetation where the focus is on density of physical distribution.
Min's hair is naturally thin, so she uses special products to add volume.
collocation: thin hair = not dense
The grass on the hillside was thin, with patches of bare soil showing through.
Tunde planted lavender in the thin spots of his garden, hoping the poor soil would finally grow something.
The trees at the forest's edge are thin and let sunlight reach the ground.
The vegetation on the mountain top is thin because the wind is too strong.
用法筆記
Commonly describes hair, fur, grass, crops, trees, or other vegetation. The focus is on density of distribution rather than total quantity. Distinguish from adj/1 (physical thinness of an object) and adj/5 (a small number of people or things in a space).
thin — adverb
1. with very little thickness between two opposite surfaces; in a way that leaves s
with very little thickness between two opposite surfaces; in a way that leaves space between individual people or things
Marta sliced the cucumber thin for the salad she brought to the party.
verb + thin (adverb of result)
The morning fog lay thin over the valley near Lucía's village.
Cyrus spread the butter thin on his toast to save some for later.
Scattered thin across the wide lawn, the autumn leaves looked like gold.
Eri cut the sourdough bread thin for the cheese board she prepared.
- thickly
opposite for both thickness and density
文法句型
cut/slice/spread/scatter + thin
用法筆記
Thin as an adverb appears most often after verbs describing cutting, spreading, or distributing. In more formal writing, 'thinly' is preferred; 'thin' sounds more natural in everyday speech and recipes.