incumbent vs geology

incumbent and geology both are nouns.

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

incumbent (noun)	geology (noun)
the official who holds an office	a science that deals with the history of the earth as recorded in rocks

incumbent (adjective)	geology (adjective)
currently holding an office
necessary (for someone) as a duty or responsibility; morally binding
lying or leaning on something else