Translation guide
The English word "thin" covers many distinct concepts in Japanese, from describing people and objects to abstract qualities. The most common Japanese equivalents are 細い (hosoi) for slender objects, 薄い (usui) for flat things and weak concentrations, and 痩せている (yasete iru) for thin people. Choosing the right word depends on what is thin and in what way.
Describing a person or animal as having little body fat, or a body part as slender.
The standard way to say someone is thin (not fat). It implies a lack of body fat. Can be used positively or negatively depending on context.
彼女はとても痩せている。
She is very thin.
最近痩せたね。
You've gotten thin lately.
Used for slender body parts like arms, legs, fingers, or waist. It emphasizes slimness in shape rather than overall body fat.
Loanword from English 'slim'. Often used positively for a slender figure, especially in fashion or advertising.
A slightly derogatory or childish term for a skinny person, like 'skinny' or 'scrawny'.
Describing something long and narrow in diameter, like a stick, string, or line.
Describing something flat and lacking thickness, like paper, a book, or a slice.
Used for flat things with little depth: paper, cloth, boards, etc. Also for thin layers.
Describing a substance that is watery, weak, or not thick, like soup, paint, or air.
Used for liquids, colors, flavors, etc. that are weak or diluted. Also for thin air at high altitudes.
Describing hair that is not dense, or balding.
Used for hair that is thinning or sparse. Also for eyebrows, beards, etc.
Describing a small number of people in a large space, or low turnout.
Commonly used for thin crowds, sparse attendance, or scattered objects.
Describing something insubstantial or flimsy, like an excuse or evidence.
Can be used figuratively for weak, thin excuses, smiles, or reactions.
細い is for long, slender things (pencils, legs, roads). 薄い is for flat things (paper, books) and for weak concentrations (thin soup, thin hair, thin air). 痩せている is specifically for people and animals being thin (low body fat). Using the wrong one can cause confusion: 薄い人 means a shallow/superficial person, not a thin person.
Do not use 細い to describe a person's overall body type. 細い人 means a person with a slender build (narrow frame), not necessarily thin. To say someone is thin (not fat), use 痩せている.
She has thin arms.
細い指ですね。
You have thin fingers.
I want to maintain a slim figure.
あの子は痩せっぽちだ。
That kid is a skinny little thing.
The primary word for thin, long objects. Used for pencils, threads, roads, rivers, etc. Focuses on small cross-section.
Emphasizes that something is both thin and long. Often used for shapes like rectangles, leaves, or fingers.
細長い箱に入っている。
It comes in a thin, long box.
薄い紙に書いてください。
Please write on thin paper.
この本は薄いからすぐ読める。
This book is thin so I can read it quickly.
このスープは味が薄い。
This soup tastes thin/weak.
山の上は空気が薄い。
The air is thin on the mountain top.
Means watery, thin, or lacking body. Often negative when describing food or drink.
このカレーは水っぽい。
This curry is thin/watery.
父は髪が薄くなってきた。
My father's hair has gotten thin.
Means sparse, thin, scattered. Can describe hair, vegetation, attendance, etc.
彼のひげはまばらだ。
His beard is thin/sparse.
観客はまばらだった。
The audience was thin/sparse.
Literally 'few people passing', used for thin traffic or empty streets.
夜は人通りが少ない。
The streets are thin/empty at night.
彼の言い訳は薄い。
His excuse is thin/weak.