not filled or occupied; available to be used

The hospital has no vacant beds. 这家医院没有空床位。

Compare: engaged (IN USE)

A vacant job is one that no one is doing and is therefore available for someone new to do

The position fell (= became) vacant when Rodman was promoted. 罗德曼提升之后这个职位就空缺了。

showing no interest or mental activity

She had a vacant look/expression on her face. 她一脸的茫然。