na-adjective, noun or participle which takes 'suru'
completely satisfied; as pleased as can be
Expresses a high degree of satisfaction, often used in casual or emphatic contexts.
この料理には大満足です。
I am completely satisfied with this dish.
旅行は大満足だった。
The trip was as pleasing as could be.
満足 means 'satisfaction' or 'being satisfied'; 大満足 adds emphasis, meaning 'great satisfaction' or 'completely satisfied'.
Compound of 大 (dai, 'big, great') and 満足 (manzoku, 'satisfaction'). The exact historical derivation is uncertain, but the meaning is transparent from its components.