diligent application (to work or study); cultivating one's character by studying hard; mutual encouragement (to improve); working hard together; friendly rivalry
polish (jewels); cultivation
diligent application (to work or study); cultivating one's character by studying hard; mutual encouragement (to improve); working hard together; friendly rivalry
to polish; to shine; to brush (e.g. teeth); to refine (e.g. a skill); to improve; to cultivate