This is the full sentence:


なる here means "to reach a certain state." The rest is easy to translate.

The only thing that confuses me is く. What does it mean here and why is it necessary?

  • 1
    What did you expect it to be? If that く wasn't there. Related question here.
    – Tommy
    Commented Nov 12, 2018 at 8:39
  • @Tommy I expected the same sentence but without that character.
    – wyc
    Commented Nov 12, 2018 at 11:35

2 Answers 2


You have to learn how to conjugate i-adjectives when it comes to expressing change using なる. I recently answered a similar question, but that was posed in a different way so let me just get to the bottomline of what you want to know.

The basic construction rule when expressing change with なる is the following.:

い-adj (-い+く)+なる Example たかい >>> たかくなる

な-adj (-な+に)+なる Example きれいな >>> きれいになる

nouns (+に)+なる Example せんせい >>> せんせいになる

And when it comes to negative:

い-adj (-い+く)+ならない Example たかい >>> たかくならない

な-adj (-な+に)+ならない Example きれいな >>> きれいにならない

nouns (+に)+ならない Example せんせい >>> せんせいにならない

In your case 悪い is an i-adjective, hence 悪くなる.


Simply put, ~く is one possible conjugated form of i-adjectives, used in negative forms and when the adjective modifies a verb or another adjective (examples below).

くらい  → くらない (negative)

わるい  → わるなる (adjective+verb)

おいしい → おいし食べる (adjective+verb)

たのしい  → たのし過ごす (adjective+verb)

やすい   → やすておいしい (adjective+adj)


  • 1
    I think your answer is missing something important. That 〜く is one possible conjugated form does not explain when this form is used.
    – virmaior
    Commented Nov 13, 2018 at 14:19
  • @virmaior edited to address your comment.
    – kandyman
    Commented Nov 13, 2018 at 16:55

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