This is the 15833rd most frequent Korean word.
부가적인
Additional; supplementary.
Here, '부가적인' is used to modify '비용' to indicate additional or extra costs.
이 프로젝트에는 부가적인 비용이 필요합니다.
This project requires additional costs.
In this sentence, '부가적인' describes '설명' to mean supplementary or further explanation.
부가적인 설명이 필요하지 않다고 생각합니다.
I don't think additional explanation is necessary.
'부가적인' in this example qualifies '업무' to express extra or supplementary tasks.