Necessary, Needed, Essential
noun, な adjective
It's certain that you need it. This thing is necessary. It is needed.
ひつよう
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.
スーパーに行くけど、何か必要なものはありますか?
I'm going to a supermarket. Do you need anything?
バスをおりてから、少し歩く必要があります。
You need to walk a little after getting off the bus.
その服の山、本当に全部必要なんですか?
Do you really need everything in that mountain of the clothes?