president vs presidential

president is a noun but presidential is not a noun.

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

president (noun)	presidential (noun)
the chief executive of a republic
an executive officer of a firm or corporation
the head administrative officer of a college or university
the officer who presides at the meetings of an organization

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