An intransitive verb meaning that something (e.g., luggage) is lost or missing—its whereabouts are unknown.
駅で財布がなくなっていることに気づいた。
I realized my wallet was missing at the station.
鍵がまたなくなった。どこに置いたか覚えていない。
My keys have gone missing again. I don't remember where I put them.
大切な書類がなくなり、会社は大騒ぎになった。
Important documents went missing, and the company panicked.
Indicates something has been used up or run out (stock exhausted), or that something no longer occurs (e.g., a practice or event stops happening).
パンがなくなったから買いに行ってくるね。
We're out of bread, so I'll go buy some.
冬になると花はなくなり、庭は寂しくなる。
When winter comes, the flowers are gone and the garden becomes lonely.
その町では古い祭りが次第になくなってきた。
The old festival in that town has gradually disappeared.
Describes intangible things like pain, confidence, or dreams disappearing or being lost (e.g., 'confidence disappears', 'the pain goes away').
手術後、痛みはだんだんなくなった。
After the operation, the pain gradually went away.
失敗が続いて自信がなくなってしまった。
After repeated failures, my confidence disappeared.