presidential vs President

presidential is not a noun while President is a noun.

Word	Noun	Adjective	Verb	Adverb
presidential	No	Yes	No	No
President	Yes	No	No	No

presidential (noun)	President (noun)
	the office of the United States head of state
	the person who holds the office of head of state of the United States government

presidential (adjective)	President (adjective)
befitting a president
relating to a president or presidency