He was busy schmoozing with various people at the party, hoping to expand his network.

schmoozing 是动词 schmooze 的现在分词形式。schmooze 来自意第绪语，意思是"闲聊、社交性谈话"，通常指为了建立关系或获取信息而进行的非正式交谈，带有社交目的性。