剣を落として舟を刻む

表記・読み：けんをおとしてふねをきざむ

1
to not be getting with the times; to be unaware that things are changing; to drop one's sword (in the river) and carve (a mark) on the boat (to mark the spot where the sword was dropped)
expressions (phrases, clauses, etc.)from a story in Master Lü's Spring and Autumn Annalsidiomatic expression