surrogate
/ˈsʌrəgeɪt; `sʌrəˌɡet/ n
~ (for sb/sth) (fml 文) person or thing that acts or is used instead of another; substitute 替代的人或事物; 替代者; 代理人; 替代物; 代用品
Fiction is a poor surrogate for real experience. 小说中的事远逊於实际体验.
[attrib 作定语]
a surrogate mother, ie a woman who has a baby on behalf of another who is unable to have babies herself 代母（代不育女子生育的女子）.