研みがか

みがか · migaka

JLPT N5 verb 未然形

研か is the negative stem of 研く — to polish, to shine, to burnish, to scour, to scrub, to brush (teeth), to grind (e.g. a lens).

to refine (a skill, etc.), to improve, to hone, to polish (up), to cultivate (one's character)

Full entry for 研ぐ

How it’s built

研く研か

Negative stem (未然形). Never used alone — it is the base for ない (not), れる/られる (passive), せる/させる (causative): 書か → 書かない.

研く is a godan verb (u-verb), so it follows that pattern.