单词：vacantly 

副词

• 
  [1.r.vacantly] (同义词:[vacantly(adv 空虚地；茫然若失地 )]  )
• 
  注释列句：in a vacant manner; "she was staring vacantly into the room"
• 属于名词 -> [vacant( adj. 空的, 空白的, 空灵的, 头脑空虚的, 神情茫然的, 空闲的, 空缺的 )]