Definition of 磨穿鉄硯 (ませんてっけん)

noun
showing unyielding diligence in one's studies, wearing a hole through one's metal inkstone from constant studying(yojijukugo)
Related Kanji
grind, polish, scour, improve, brush (teeth)
穿 put on (to the feet), dig, pierce, drill
iron
inkstone