1. Godan verb with 'ru' ending, Intransitive verb

   1.

   to become blunt; to grow dull

2. 2.

   to become less capable; to weaken; to falter

Example sentences

• 「最近、書道してないんだ」「そうなんだ。たまにはしないと腕が鈍るよ」

  "I haven't done any calligraphy recently." "Oh, really? Well, if you keep putting it off, you'll lose your touch."

• 「最近、書道してないんだ」「そうなんだ。たまにはしないと勘が鈍るよ」

  "I haven't done any calligraphy lately." "Is that so? If you don't practice every so often you'll start to lose your touch."