勘が鈍る

Meaning

1. expv5r
   to become insensitive; to become less perceptive; to lose one's touch; to get out of practice

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."