While studying yesterday, I came across two words with the suffix さ:

無邪気さ(translated as innocence) and 寛大さ (translated as generosity).

1) What's the difference between these words and the words without the さ? I thought that な-adjectives without the な are already nouns.

2) Can I add さ to other 形容動詞 too, for example 人気さ or 便利さ?

1 Answer 1


1) I know that some people like to categorize な-adjectives in this way, but IMHO it's silly. There are many な-adjectives that don't work as nouns without the な, and there are many nouns that don't work as な-adjectives by adding な.

2) さ is quite productive, so in general, I want to say yes. However:

  • Although everybody will understand 人気さ (and I can find many examples of it on Google), it sounds (to me) a bit clumsy or childish, since 人気 is already also a noun meaning the same thing.
  • 便利さ is completely grammatical, and is in fact probably the most common way to express the concept. However, there is often another more technical word expressing the same thing, in this case for example 便益.
  • I understand. I know that you can't just add な to nouns, but I did think that most な-adjectives without な were just nouns. I'll just have to be careful as I progress.
    – newyorkaru
    Jun 4, 2015 at 1:53
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    The situation is not always simple... for example, when I search kotonoha.gr.jp/shonagon for occurrences of 寛大, I do find a few examples of it being used as a noun, but mostly in slightly archaic and/or poetic use. 寛大さon the other hand gives many results with no such overtones. And there are cases, like 静か, that definitely cannot be used as nouns in the usual sense of the word.
    – dainichi
    Jun 4, 2015 at 2:13
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    I think you're right, though perhaps the problem is in how "noun" is defined. Some definitions center around appearing before the copula だ, which I think goes back to Bernard Bloch, but I think a better definition would include (for example) the possibility of functioning as subject or object.
    – user1478
    Jun 4, 2015 at 5:46

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