Translation guide
Describes a state of poor physical or mental health, or something that causes it. Japanese uses different words depending on whether you're talking about a person's condition, a habit, food, or an environment.
Describing someone who is not well, often chronically or in a weakened state.
General term for being unhealthy, often used for lifestyle-related poor health. Can describe a person or a habit.
彼は不健康な生活を送っている。
He leads an unhealthy lifestyle.
不健康そうに見える。
You look unhealthy.
Literally 'physical condition is bad'. Used when someone feels unwell, often temporarily.
今日は体調が悪いです。
I'm feeling unwell today.
Constitutionally weak or sickly; implies a long-term delicate health condition.
彼女は病弱な子供だった。
She was a sickly child.
Describing food, eating habits, or diet that negatively affect health.
Common phrase meaning 'bad for the body'. Used for food, habits, etc.
ファストフードは体に悪い。
Fast food is unhealthy.
夜更かしは体に悪いですよ。
Staying up late is unhealthy.
Literally 'not good for health'. Slightly more formal than 体に悪い.
その食事は健康に良くない。
That diet is unhealthy.
Direct translation 'unhealthy food'. Understandable but less natural than 体に悪い.
May sound slightly stiff or translated. Prefer 体に悪い in conversation.
不健康な食べ物ばかり食べている。
I eat nothing but unhealthy food.
Describing an unhealthy mind, obsession, or emotional condition.
Unhealthy mental state. Used in psychological contexts.
それは不健康な精神状態だ。
That's an unhealthy state of mind.
Mentally not good; can describe a habit or situation that harms mental health.
SNSをやりすぎるのは精神的に良くない。
Spending too much time on social media is mentally unhealthy.
Describing a workplace, relationship, or situation that is harmful to well-being.
Harmful environment; often used for toxic workplaces or living conditions.
あの職場は有害な環境だ。
That workplace is an unhealthy environment.
Unwholesome or unhealthy relationship. 不健全 implies something morally or socially unsound.
不健全な関係を断ち切るべきだ。
You should end that unhealthy relationship.
Describing a pale, thin, or sickly look.
Literally 'complexion is bad'. The most natural way to say someone looks unhealthy or pale.
顔色が悪いけど、大丈夫？
You look pale. Are you okay?
Pale, often with a bluish tint; can imply sickness or fear.
彼は青白い顔をしている。
He has an unhealthy pallor.
Saying 不健康な食べ物 is grammatically correct but sounds like a textbook translation. In daily conversation, 体に悪い is much more natural.
ラーメンは体に悪いけど、好きだ。
Ramen is unhealthy, but I like it.
不健康 describes a state of being unhealthy (person, lifestyle). 体に悪い describes something that causes poor health (food, habit). Use 体に悪い for external causes.