Translation guide
Expresses the process of losing weight or becoming slender. Japanese distinguishes between natural thinness, intentional weight loss, and emaciation.
The speaker actively tries to become thinner through diet, exercise, etc.
The most common verb for losing weight or becoming thin, often implying intentional effort.
You've lost weight recently, haven't you?
I want to lose weight by dieting.
Literally 'body weight decreases', a neutral way to say one's weight has gone down.
My weight decreased after exercising.
Borrowed from English 'slim', often used in fashion or beauty contexts.
You look slim in this dress.
The person becomes thinner without deliberate effort, often due to health, stress, or aging.
The person becomes extremely thin, often due to starvation or severe illness.
Emphasizes extreme thinness, often with a negative connotation.
The refugees were emaciated from hunger.
Describes a haggard, gaunt appearance, often from exhaustion or illness.
He became gaunt after being hospitalized.
Something becomes thinner in dimension, like a book, fabric, or layer.
痩せる is for living things losing weight/flesh. 細くなる is for slender shape (people or objects). 薄くなる is for flat things or low density.
She lost weight but is not yet slender.
English 'become thin' can be awkward if directly translated as 薄くなる for people. Use 痩せる for weight loss.
He became thin. (incorrect for a person)