An emphatic form of 'still' meaning 'still', 'much more', or '(not) yet' — indicating that a state continues or that more remains to come.
この問題はまだまだ難しい。
This problem is still very difficult.
彼の実力はまだまだだが、努力している。
His ability is still lacking, but he is working hard.
時間はまだまだあるから焦らないでいい。
There's plenty more time, so you don't need to rush.
Used in set phrases like 'まだまだだ' to mean 'there's still a long way to go' or 'not there yet'.
新人の彼に対して先輩は『まだまだだ』と言った。
The senior said to the newcomer, 'You still have a long way to go.'
日本語の勉強はまだまだこれからだ。
There's still a long way to go in my Japanese studies.
結果は良かったが、先生は『まだまだだ』と厳しかった。
Although the results were good, the teacher sternly said, 'Not yet; you still have a long way to go.'