（某人）义不容辞；（某人）必须履行
to be necessary for someone
She felt it incumbent upon/on her to raise the subject at their meeting. 她感到她有义务在他们的会上提出这个问题。
It is incumbent on us all to speak out when we see injustice.
We believe it is incumbent upon scientists to do a better job of communicating with the public.
It is incumbent on the fuel industry to work cooperatively with the government.
It is incumbent on the board of directors to take swift action.
See also: incumbent adjective