What is the full sentence? That phrase is not one phrase. It might be a part of the sentence like following. 부족한 것은 채우고 넘치는 것은 비워라. Supply the lack and empty the abundance

채우다 = to fill up. 넘치다 = to spill out, overflow. 채우고 넘치는 것 (or 채워서 넘치는 것) is thus to fill something up until it overflows, if you take it literally. But it sounds like a poetic expression hinting at dedication and devotion. It seems to suggest something (probably love, compassion, friendship, etc) for which you give of yourself without holding back. You might translate it as "(giving) abundantly, and still more", "full to the brim, and then some", "all the way, and further still", etc. but it's the kind of poetic phrase you can't define a precise meaning for.