frontbencher
noun [ C ] uk/ˌfrʌntˈben.tʃər/ us/ˌfrʌntˈben.tʃɚ/
（英国议会中）在前排就座的议员
a politician who sits on the front benches of the UK parliament
He is the government's longest serving frontbencher. 他是政府中任期最长的前座议员。
Compare: backbencher