/ ɪnˈkʌmbənt; NAmE / noun , adjective
■ noun
a person who has an official position :
the present incumbent of the White House
■ adjective
1.
[ only before noun ] having an official position :
the incumbent president
2.
incumbent upon / on sb ( formal ) necessary as part of sb's duties :
It was incumbent on them to attend.
••
WORD ORIGIN
late Middle English (as a noun): from Anglo-Latin incumbens , incumbent- , from Latin incumbere lie or lean on, from in- upon + a verb related to cubare lie.