Young Person
noun, の adjective
A young someone is a young person.
The reading for this one is a pain. 若 is the same as what you learned with the kanji (わか), but 者 is もの, which isn't what you learned. Think of this: A young person does what they want. They don't follow tradition or do anything the way you'd want them to, just like the reading of this word. Also, their actions make you really want to moan (もの) because ugh, young people. Get off my lawn.
その若者は、公園でセミを細かくかんさつしていました。
That young person was observing cicadas very closely in the park.
この件には、あの若者の金が絡んでいるらしいよ。
Apparently that young person's money is involved in this matter.
この若者はすごいよ。大物になる前にサインをもらっておいた方がいいよ。
This young man is terrific. You should get his autograph before he becomes a big-shot.