noun
knife grinder; sword sharpener; polisher
A person who professionally sharpens blades or polishes items such as swords, mirrors, or knives.
祖父は昔、研ぎ師として刀を研いでいた。
My grandfather used to work as a sword sharpener, polishing swords.
包丁の切れ味が悪くなったので、研ぎ師に頼んだ。
The kitchen knife got dull, so I asked a knife grinder to sharpen it.
The verb meaning 'to sharpen' or 'to polish'; 研ぎ師 is the person who performs this action professionally.
Compound of 研ぎ (togi, the continuative form of 研ぐ 'to sharpen, polish') and 師 (shi, 'master, specialist').