Sudden, Urgent, Emergency, Steep
adverb, な adjective
This takes its meaning from the sudden part of the kanji, meaning it's sudden, urgent, or an emergency!
きゅう
This has the same reading as the kanji you learned, meaning you know the reading!
それはいくら何でも急すぎない？
Isn't that too sudden, by any measure?
それはとても急な知らせだったので、彼女はビックリしました。
It was such sudden news that she was surprised.
急な仕事を引き受けちゃったので、今日の帰りは九時くらいになります。
I took on an urgent job, so I will be home around nine o'clock today.