noun, noun or participle which takes 'suru', transitive verb
training; practice; drilling; cultivation; improvement
Refers to rigorous, repeated practice or training to polish skills, character, or abilities. Often used in contexts of martial arts, sports, or personal development. Can be used as a noun or with する as a transitive verb.
彼は毎日剣道の練磨に励んでいる。
He devotes himself daily to the training of kendo.
精神を練磨するために座禅を組む。
I practice zazen to cultivate my mind.