cheerio
/ˌtʃɪərɪˈəʊ/exclamation
1- Brit. informal used as an expression of good wishes on parting; goodbye〈英, 非正式〉（分别时祝福用语）保重; 再会！
1.1
- dated used to express friendly feelings towards one's companions before drinking〈旧〉（祝酒用语）干杯！