Discard
Reject, Death
independent noun, in compounds
When a plant or an animal dies you have to discard it. You can't just keep it sitting around the house after death, that's weird.
This has the same reading as the kanji you learned, meaning you know the reading!
こないだの原稿は没になってしまった。
The manuscript was rejected the other day.
申し訳ありませんが、この案は一旦没にしてください。
I'm sorry, but I'm afraid you're going to have to discard this idea for now.
その歌手は、2015年12月1日没、とされているが、真相は定かではない。
The singer is said to have died on December 1, 2015, but the facts are not clear.