鈍る

にぶる

to become less capable, to grow dull, to become blunt, to weaken

JLPT N1

Character Breakdown

Meaning and Usage

The verb 鈍る (にぶる) primarily means "to become dull" or "to become less sharp," and it is often used to describe physical objects like blades or senses such as reaction speed and concentration. It can also refer to a decline in mental or physical abilities.

Common Contexts

鈍る is frequently used when talking about tools (like knives or blades) becoming blunt after use or disuse. It also describes human faculties such as reflexes, concentration, or sensitivity becoming less sharp, especially with aging or lack of practice.

Collocations and Patterns

  • 鈍る + 感覚 (かんかく): to have dulled senses
  • 反応が鈍る: reactions become slow
  • 集中力が鈍る: concentration weakens
  • 刃が鈍る: blade becomes dull

These collocations help express physical or mental dullness clearly.

Register and Nuance

鈍る is a neutral verb, suitable for both formal and informal contexts. It often implies a gradual decline rather than a sudden change.

Common Learner Mistake

Learners sometimes confuse 鈍る with 怠る (おこたる), which means "to neglect" or "to be lazy." Remember, 鈍る focuses on becoming dull or less sharp, not on neglecting an action.

Example Sentences

ながいあいだつかわなかったないふのはがにぶってしまった。

The blade of the knife that hadn't been used for a long time has become dull.

としをとるとはんのうがにぶることがおおい。

As people age, their reactions often become slower.

さいきん、しゅうちゅうりょくがにぶっているとかんじる。

Lately, I feel my concentration has weakened.