Viet made a considerable profit on a black market deal when he was young.
Koichi studied in Japan when he was young.
You do realize that young woman is way out of your league, right?
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of young? It's young.
The reading is the same as the one you learned with the kanji. Oh how nice it is to be young and to be able to remember that.