1. 缺少的；不足的；没有的
    If something or someone is lacking in a particular quality, they do not have any of it or enough of it.

    e.g. ...if your hair is lacking in lustre and feeling dry...
           如果头发缺少光泽且干枯
    e.g. She felt nervous, increasingly lacking in confidence about herself...
           她感到紧张，对自己越来越没有信心。

1. nonexistent

    e.g. the thumb is absent
           her appetite was lacking

    Synonym: absentmissingwanting