I. in ‧ cum ‧ bent 1 /ɪnˈkʌmbənt/ BrE AmE noun [countable] formal
[ Date: 1400-1500 ; Language: Latin ; Origin: present participle of incumbere 'to lie down on' ]
someone who has been elected to an official position, especially in politics, and who is doing that job at the present time:
In the June elections, Morris easily defeated the incumbent, Tom Smith.
II. incumbent 2 BrE AmE adjective formal
1 . it is incumbent upon/on somebody to do something if it is incumbent upon you to do something, it is your duty or responsibility to do it:
It is incumbent upon parents to control what their children watch on TV.
2 . the incumbent president/priest/government etc the president etc at the present time