Task, Use, Duty, Service, Business, Purpose
noun, suffix
The kanji and the word are exactly the same. That means they share meanings as well.
よう
This one uses the on'yomi reading, which you've learned from the kanji already!
今日は、なにも用がない。
There is nothing to do today.
用もないのにラインしてくんじゃねーよ。
Don’t text me on LINE unless you have a good reason.
これは冬用のジャケットです。
This is a winter jacket.