current vs incumbent

current and incumbent both are nouns.

Word	Noun	Adjective	Verb	Adverb
current	Yes	Yes	No	No
incumbent	Yes	Yes	No	No

current (noun)	incumbent (noun)
a steady flow of a fluid (usually from natural causes)	the official who holds an office
dominant course (suggestive of running water) of successive events or ideas
a flow of electricity through a conductor

current (adjective)	incumbent (adjective)
occurring in or belonging to the present time	currently holding an office
	necessary (for someone) as a duty or responsibility; morally binding
	lying or leaning on something else