a person appointed to act for another; deputy.

(in some states) a judicial officer having jurisdiction over the probate of wills, the administration of estates, etc.

the deputy of an ecclesiastical judge, esp. of a bishop or a bishop's chancellor.

a substitute.

a surrogate mother.

regarded or acting as a surrogate

a surrogate father.

involving or indicating the use of a surrogate mother to conceive or carry an embryo

surrogate parenting.

to put into the place of another as a successor, substitute, or deputy; substitute for another.

to subrogate.

noun

real

noun

substitute agent , alternate , backup , delegate , deputy , expediency , expedient , fill-in , makeshift , pinch hitter , proxy , recourse , refuge , replacement , representative , resort , resource , stand-in , stopgap * , sub * , substitute

verb

supersede , supplant