Two hands clapping emoji, which when used multiple times can be used as a round of applause.
Many people use it in its direct meaning of applause, i.e., appreciation of someone's success or talent, skillfulness or achievements, for example, as a part of a congratulations message.
However, not less often, it is used with a sarcastic meaning (i.e., as a sign that someone's actions or behavior are just the opposite of those deserving genuine applause).
Clapping Hands was approved as part of Unicode 6.0 in 2010 under the name “Clapping Hands Sign” and added to Emoji 1.0 in 2015.
U+1F44F
? Clapping hands sign