糠に釘

糠に釘【ぬかにくぎ】

Alsoぬかに【ぬかにくぎ】ぬかにくぎ

expressions (phrases, clauses, etc.); noun (common) (futsuumeishi)

having no effect; waste of effortidiomatic expression

This expression is used to describe a situation where an action taken yields no results or is completely ineffective, similar to the idiom "like putting a nail in rice bran."

He explained it several times, but everyone did not understand. It was like trying to put a nail in rice bran.

国語辞典Japanese definitions

きごう（ぬかにくぎ糠に釘をうちつけて打ち付けてもてごたえ手応えがないことからきごう）てごたえ手応えやききめ効き目がまったくない全くないことのたとえ喩え。すすんで進んで、そのようなてごたえ手応えのない無いものにはたらきかける働きかけることはむだ無駄であることのいましめ戒め。

Wiktionary

糠に釘【ぬかにくぎ】

Alsoぬかに【ぬかにくぎ】ぬかにくぎ

expressions (phrases, clauses, etc.); noun (common) (futsuumeishi)

having no effect; waste of effortidiomatic expression

This expression is used to describe a situation where an action taken yields no results or is completely ineffective, similar to the idiom "like putting a nail in rice bran."