ADJ [ADJ n]后座（议员）的;普通（议员）的 A backbench MP is a Member of Parliament who is not a minister and who does not hold an official position in his or her political party. 后座（议员）的;普通（议员）的 [British, Australian]
...the Conservative backbench MP Sir Teddy Taylor.
保守党下院普通议员泰迪·泰勒爵士
Such a motion is considered a test of backbench opinion.