Verb (5-dan, る, intransitive)
Usually written in kana
1. to be lost (e.g. luggage); to be missing
大変です、私の大切なものがなくなりました。This is terrible, something precious of mine has gone missing.
2. to be used up; to be run out; to be exhausted; to be consumed; to be reduced to zero; to not occur any more
お買い物する時間がなくなっちゃうよ。I'm going to run out of time to go shopping.
3. to disappear (e.g. pain); to be lost (e.g. a dream, confidence)
でも自信がなくなったの。But I lost my confidence.