Emergency, Extreme, Unusual
noun, な adjective, の adjective
When an injustice to what's normal is being committed, that makes it an emergency! Although it's less common, this can also be used as a な adjective. In that case, it means extreme or unusual.
ひじょう
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
この非常ブレーキ、こわれてるかもしれないよ。
I think this e-brake might be broken.
急に非常ベルが鳴り出して、びっくりしました。
The emergency alarm suddenly went off and I was surprised.
ポテトチップスは非常食にピッタリです。
Potato chips are a perfect emergency food.