incumbent
/ɪnˈkʌmbənt; ɪn`kʌmbənt/ adj
1 [pred 作表语]
~ on/upon sb (fml 文) necessary as part of sb's duty 有责任; 有义务; 必须履行
It is incumbent upon all users of this equipment to familiarize themselves with the safety procedure. 凡使用这种设备的人都应熟悉安全程序.
2 [usu attrib 通常作定语]
holding the specified official position; current 现任的; 在职的
the incumbent president 现任总裁. incumbent, n person holding an official position, esp in the church 现任者, 在职者（尤指神职）
the present incumbent of the White House, ie the US President 现任美国总统.