研とぐ

godan verb (-gu), transitive verb

sharpen; hone; whet; grind

Transitive verb for making a blade, point, claw, or similar edge sharp, often by using a whetstone or abrasive. 研ぐ is the usual spelling; 砥ぐ highlights the whetstone/sharpening nuance.

• 父ちちは砥と石いしで包ほう丁ちょうを研といだ。

  My father sharpened the kitchen knife with a whetstone.

• 猫ねこが柱はしらで爪つめを研といでいる。

  The cat is sharpening its claws on the post.

godan verb (-gu), transitive verb

wash rice

Used specifically for washing rice by rubbing the grains in water before cooking. This sense as especially associated with 磨ぐ, though 米を研ぐ is also a very standard spelling.

• 米こめを研といでから炊すい飯はん器きに入いれる。

  Wash the rice before putting it in the rice cooker.

godan verb (-gu), transitive verb

scour; polish; burnish

Used when rubbing or abrading a surface to clean it, smooth it, or bring out a shine. Compared with 磨く, this often suggests a more abrasive or craft-like process.

• 職しょく人にんは金きん属ぞくの表ひょう面めんを研といで、鏡かがみのように仕し上あげた。

  The craftsman polished the metal surface until it had a mirror-like finish.