polishing one's sword; improving one's talents or knowledge
Rare literary term. Literally refers to polishing a sword, and figuratively to refining one's skills or learning. Not used in everyday speech.
磨淬 is an old word meaning to polish a sword, and by extension, to refine one's learning or skills.
Compound of 磨 (polish) and 淬 (temper, quench). The exact historical derivation is uncertain; it is a classical Chinese-derived term.