The emoji may be a synonym for a greeting or saying goodbye to someone or something. But, sarcastically, it may even mean wishing someone or something would go away.
This emoji can be used to convey a sense of not being friends any more when used on WeChat in China.
Waving Hand was approved as part of Unicode 6.0 in 2010 under the name “Waving Hand Sign” and added to Emoji 1.0 in 2015.
U+1F44B
? Waving hand sign