(にぶ)

にぶる
verb, godan
to become dull; to weaken; to slow down
1. to become dull; to lose sharpness
For a blade or edge to lose its sharpness through use or neglect.
包丁(ほうちょう)()(あじ)(にぶ)った。
The kitchen knife has gone dull.
使(つか)(つづ)けるとハサミの()(にぶ)る。
Scissors get dull if you keep using them.
(なが)(あいだ)()いでいないので、()がだいぶ(にぶ)っている。
Since I haven't sharpened it in a long time, the blade has become quite dull.
2. to weaken; to slow down; to deteriorate
For skills, senses, speed, or determination to decline or lose their edge. A figurative extension of the literal meaning.
(かん)(にぶ)る。
One's intuition weakens.
練習(れんしゅう)をサボると(うで)(にぶ)る。
If you skip practice, your skills deteriorate.
(さむ)さで()感覚(かんかく)(にぶ)って、うまくボタンが()せなかった。
My hands were so numb from the cold that I couldn't press the buttons properly.

(にぶ)る is an intransitive godan verb. The transitive form is (にぶ)らせる (to make dull, to cause to weaken).

ASPECT (ている):
(にぶ)っている describes the resulting state of being dull or weakened.

COMMON COLLOCATIONS:

  • ()(にぶ)る (a blade becomes dull)
  • (かん)(にぶ)る (intuition weakens)
  • (うで)(にぶ)る (skills deteriorate)
  • (うご)きが(にぶ)る (movements slow down)
  • 感覚(かんかく)(にぶ)る (sensation becomes numb)

RELATED WORDS:
The adjective (にぶ)い (dull, slow) shares the same kanji. Compare with (するど)い (sharp) and (するど)くなる (to become sharp), which express the opposite direction.