vicar
A Christian clergyman who acts as a deputy or substitute for a parish priest or bishop. The term is used in Anglican and other denominational contexts.
He was appointed as the vicar of that church.
牧師 is a general term for a pastor or minister, while 代理牧師 specifically refers to a vicar who serves as a deputy.
Compound of 代理 (dairi, 'proxy, deputy') and 牧師 (bokushi, 'pastor, minister').