a social butterfly直译社交蝴蝶，引申为善于交际的人，会应酬的人。

【例句】
Jack is such a social butterfly. He became friends with more than 100 people in the party yesterday!
Jack可真善于交际啊！在昨天聚会上交了不下一百个朋友！

I don't like that young lady; she's too much of a social butterfly.
我不喜欢那个年轻女子，她是个十足的交际花。