adverb
Indicates that a state or action continues beyond an expected point, often with a nuance of 'even now' or 'still more'. Used in both positive and negative contexts.
雨はなおも降り続けた。
The rain continued to fall still.
彼はなおも努力を続けた。
He continued his efforts further.
Problems still remain.
まだ simply means 'still' or 'not yet', while なおも emphasizes continuation beyond expectation or adds a sense of 'even more'.
なお can mean 'still' or 'furthermore', but なおも is more emphatic and often implies persistence or an unexpected continuation.
Derived from the adverb なお (still, furthermore) with the emphatic particle も, reinforcing the sense of continuation.