1. He is her lover; she is his mistress.
    他是她的情夫，她是他的情妇。

1. lover的反义词

1. 恋人：点击下载 <恋人>>(Lover)修正版20集全+OST/韩剧热线/韩语中字/HDTV[RMVB]<恋人>>(Lover)修正版20集全+电子刊特别版/韩剧热线/韩语中字/HDTV[RMVB]

1. （非婚的）爱人，情人
    Someone''s lover is someone who they are having a sexual relationship with but are not married to.

lover

    e.g. Every Thursday she would meet her lover Leon...
           每周四她都会和情人利昂幽会。
    e.g. He and Liz became lovers soon after they first met.
           他和莉兹初次见面后不久就成了情侣。

2. 热爱者；爱好者；发烧友
    If you are a lover of something such as animals or the arts, you enjoy them very much and take great pleasure in them.

    e.g. She is a great lover of horses and horse racing...
           她热爱马匹和赛马。
    e.g. Are you an opera lover?
           你是歌剧发烧友吗？

1. a person who loves someone or is loved by someone

2. a significant other to whom you are not related by marriage

3. an ardent follower and admirer

    Synonym: fanbuffdevotee