In the manga title, 「ひのさんのバカ」, why is the の particle used?


Does it mean "Hino-san's idiot" (indicating possession) or "Hino-san _is_ an
idiot"?

If it's the latter, why shouldn't it be "Hino-san **は** baka"?




Possession is just one of the many meanings of の, and does not apply in this
case.「ひのさんのバカ」 here means ひのさん **が** バカ, i.e. "Hino is an idiot" (as you
suspected).

See: [How does the の work in
「日本人の知らない日本語」?](https://japanese.stackexchange.com/questions/12825/how-does-
the-%E3%81%AE-work-
in-%E6%97%A5%E6%9C%AC%E4%BA%BA%E3%81%AE%E7%9F%A5%E3%82%89%E3%81%AA%E3%81%84%E6%97%A5%E6%9C%AC%E8%AA%9E)

While this substitution mostly applies to relative clauses or double-subject
constructions (unless there is a direct object marked with を), the subject
particle が can be replaced with の in many cases.

Refer also to the Jisho definition for [の](https://jisho.org/search/%E3%81%AE)

_1. indicates possessive​ (...)_

_2. nominalizes verbs and adjectives​ (...)_

_**3. substitutes for "ga"** in subordinate phrases​. (See also が):
１００人近くの人がいたが、ほとんど会ったことのない人たちだった。There were almost 100 people, few of whom I
had seen before. (...)_




The の is appositive (同格). [The Wiktionary entry for
の](https://ja.wiktionary.org/wiki/%E3%81%AE#%E6%A0%BC%E5%8A%A9%E8%A9%9E) may
help:

> の  
>  助詞  
>  格助詞  
>  5. 上の語と下の語が **同格** であることを表す。
>
>   * 部長の山田さん。
>   * 妹の薫さんが来てたよ。 (...)
>     1. **悪態をつくときに用いられる表現** 。
>       * お兄ちゃん **の** バカ。
>       * 部長 **の** わからず屋が。
>

The appositive の has been explained multiple times in this site:

  * [What's the difference between 日本人の学生 and 日本の学生 ?](https://japanese.stackexchange.com/q/40892/9831)
  * [Confusing use of の](https://japanese.stackexchange.com/q/55540/9831)
  * [Translation of Hosutofamiri- no Minasan (ホストファミリーのみなさん)](https://japanese.stackexchange.com/q/21463/9831)
  * [How would a name be used as a non-restrictive appositive?](https://japanese.stackexchange.com/q/18638/9831)
  * [が合わせて versus の合わせて](https://japanese.stackexchange.com/q/77861/9831)

Common/familiar examples:

> 『羊 **の** ショーン』 _Shaun the Sheep_  
>  『おさる **の** ジョージ』  
>  『セロ弾き **の** ゴーシュ』 _Gauche the Cellist_  
>  「妹 **の** メイです。」  
>  「魔女 **の** キキです。こっちは黒猫 **の** ジジ。」

The Wiktionary page says one of the usages of the appositive の is
悪態をつくときに用いられる.

This has also been asked in this site:

  * [What is the role of の in 「お父さんのバカ!」](https://japanese.stackexchange.com/q/2845/9831)
  * [How does "xxxのオニ" equate to "xxx is bullying/picking on me"?](https://japanese.stackexchange.com/q/41184/9831)

Common examples:

> 「メイ **の** ばか！もう知らない！」「お姉ちゃん **の** バカー！」  
>  「ばあば **の** ケチ。もうやめなよ。」  
>  「クララ **の** 弱虫！」  
>  「ペーター **の** 意地悪。」  
>  「おばさん **の** 嘘つき！」

