1An adverb indicating that a state is continuing: "still" or "as yet."
彼はまだ会社にいる。
He is still at the office.
雨はまだ降り続いている。
The rain is still coming down.
この本はまだ読んでいない。
I still haven't read this book.
外はまだ明るいから、散歩に行こう。
It's still bright outside, so let's go for a walk.
2Used with a negative predicate as "まだ〜ない" to mean "not yet" — something expected hasn't happened.
仕事はまだ終わっていません。
The work isn't finished yet.
彼女はまだ帰ってきていない。
She hasn't come back yet.
バスはまだ来ていないから、もう少し待とう。
The bus hasn't come yet, so let's wait a bit longer.
「もう決めた？」「ううん、まだ決めていない。」
"Have you decided yet?" "No, I haven't decided yet."
3Used to strengthen a comparison, meaning "even more" or "still more" than something else.
これよりまだ大きいサイズはありますか。
Do you have a size even bigger than this?
今年の夏は去年よりまだ暑い。
This summer is even hotter than last year.
4Can mean "at least" or "relatively/comparatively" in some contexts (e.g., まだまし = "still better than nothing").
値段は高いが、まだ品質はいい。
The price is high, but at least the quality is good.
遅れたが、まだ間に合う時間だ。
We're late, but there's still relatively enough time to make it.
5Used predicatively as "まだだ" to mean something is unfinished or not yet complete; the kanji 未だ sometimes appears in formal writing.
工事はまだで、完成までもう少し時間がかかる。
The construction is still incomplete; it'll take a bit more time to finish.
「レポートは書けた？」「いや、まだだよ。」
"Did you finish the report?" "No, it's still not done."