official vs authoritative

official is a noun but authoritative is not a noun.

Word	Noun	Adjective	Verb	Adverb
official	Yes	Yes	No	No
authoritative	No	Yes	No	No

official (noun)	authoritative (noun)
someone who administers the rules of a game or sport
a worker who holds or is invested with an office

official (adjective)	authoritative (adjective)
having official authority or sanction	endowed with authority
of or relating to an office	having authority or ascendancy or influence
verified officially	of recognized authority or excellence
(of a church) given official status as a national or state institution
conforming to set usage, procedure, or discipline