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JLPT N4Word Formation

〜さ— Noun form of adjectives (degree/level)

The suffix さ converts い-adjectives and な-adjectives into nouns expressing the DEGREE or AMOUNT of that quality, like '-ness' in English.

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Pro lessonUNIT 52 · WORD FORMATION

Structure · 形

[い-adj drop い] + さ | [な-adj] + さ

Examples · 例文

  • この山の高さは3776メートルです。

    Kono yama no takasa wa sanzen nanahyaku nanajuu roku meetoru desu.

    The height of this mountain is 3,776 meters.

    高い → 高さ (height/tallness, a measurable noun)

  • 彼女の優しさに感動した。

    Kanojo no yasashisa ni kandou shita.

    I was moved by her kindness.

    優しい → 優しさ (kindness, as a noun)

  • 部屋の広さを確認してください。

    Heya no hirosa wo kakunin shite kudasai.

    Please check the size/area of the room.

    広い → 広さ (spaciousness/size)

Usage notes · 注意

  • Common さ nouns: 高さ (height), 長さ (length), 広さ (size/area), 重さ (weight), 速さ (speed), 暖かさ (warmth), 美しさ (beauty), 優しさ (kindness).
  • Nuance: さ = objective/measurable degree; み = subjective/felt quality. 暖かさ = measured warmth; 暖かみ = a sense of warmth.

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones 〜さ is tested against.

vs〜み

み gives a felt, subjective quality and attaches to a limited set of adjectives (暖かみ, 深み). さ is productive and objective, expressing a measurable degree that can be counted or compared.

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