[ ɪn'kʌmb(ə)nt ]
■ adjective
1》 ( ~ on/upon ) necessary for (someone) as a duty or responsibility.
2》 (of an official or regime) currently holding office.
■ noun the holder of an office or post.
↘ Christian Church the holder of an ecclesiastical benefice.
Origin
ME (asnoun): from Anglo-Latin incumbens , from L. incumbere 'lie or lean on'.