You use surrogate to describe a person or thing that is given a particular role because the person or thing that should have the role is not available.
例句
Martin had become Howard Cosell's surrogate son...马丁代为当起了霍华德·科塞尔的儿子。John Brown was the latest in a series of surrogate father figures in Victoria's life...在一系列曾在女王维多利亚的一生中扮演过代理父亲角色的人物中,约翰·布朗是最近的一位。
英汉词典释义
n.
替代;代理
For some people, reading travel books is a surrogate for actual travel.对某些人来说, 读游记可代替真正的旅行。
英英词典释义
Noun
1. someone who takes the place of another person
2. a person appointed to represent or act on behalf of others
Adjective
1. providing or receiving nurture or parental care though not related by blood or legal ties;