zastupnica

1. representative; agent
   Ona je zastupnica te firme za Srbiju. — She is the company's representative for Serbia.
   Na sudu ga je branila njegova pravna zastupnica. — His legal representative defended him in court.
2. (+ gen.) advocate; proponent
   Ona je poznata zastupnica ženskih prava. — She is a well-known advocate of women's rights.

For a female member of parliament, Serbia usually uses "poslanica".