I am complete beginner and I've got a question that I wish to ask you: When negating an i-adjective (-くない), should we, as in the affirmative form, omit the declarative "だ"? For example, is it "あのゲームは楽しくないだよ!" or "あのゲームは楽しくないよ!".


  • Since you are a complete beginner, this is probably not relevant to you, but to anyone else who may come across this question, it is worth mentioning that there are some dialects which allow だ after i-adjectives, such as 遠州弁 or 三河弁. – Darius Jahandarie Mar 14 '14 at 0:38

You cannot attach a 「だ」 directly to an i-adjective, either in its affirmative or negative form. (But believe me, many Japanese-learners make this mistake.)

Incorrect: 「[楽]{たの}しいだ」、「楽しくないだ」、「[大]{おお}きいだ」、「大きくないだ」, etc.

Attaching a よ or ね is correct and very natural --- affirmative or negative.

Correct: 「楽しいね」、「大きくないよ」、「かわいいね」、「おいしくないよ」, etc.

If you absolutely MUST use a だ for some reason, you can do so by inserting a 「の」 or informally, a 「ん」 between the i-adjective and the 「だ」 --- affirmative or negative.

Correct: 「楽しいのだ」、「[小]{ちい}さいんだ」、「[高]{たか}いんだ」、「[赤]{あか}いのだ」、「かわいくないのだ」、「大きくないんだ」, etc.

  • I do know that we musn't use "da" with an i-adjective when it is in its affirmative form, but I was wondering about the negative form. So thanks for your answer, it sure clears things up. – Nun Mar 14 '14 at 0:01

When negating an i-adjective, you change い for くない. The ない part is an auxiliary i-adjective, so you should omit だ, just as you do for i-adjectives.

A bullet train is fast.

A broken bullet train is not fast.

  • 3
    I would personally say だ was never there in the first place, rather than say that it's omitted. – snailcar Mar 13 '14 at 23:58
  • Sure, but the question body said "should I omit it?", so I chose to use the same language. – Earthliŋ Mar 14 '14 at 0:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.