練る
ねる · neru · JLPT N1 · verb-godan
to knead
🍞 糸 (silk) + 練: silk was kneaded to refine it, so 練る means knead or polish up
Kneading dough and polishing a plan both work something over until it is smooth. The kanji 練 carries the silk radical 糸 because raw silk was boiled and worked by hand to soften it.