postmaster general vs official

postmaster general and official both are nouns.

Word	Noun	Adjective	Verb	Adverb
postmaster general	Yes	No	No	No
official	Yes	Yes	No	No

As nouns, official is a hypernym of postmaster general; that is, official is a word with a broader meaning than postmaster general:

Other hypernyms of postmaster general include functionary.

postmaster general (noun)	official (noun)
the official in charge of the national postal service	someone who administers the rules of a game or sport
	a worker who holds or is invested with an office

postmaster general (adjective)	official (adjective)
	having official authority or sanction
	of or relating to an office
	verified officially
	(of a church) given official status as a national or state institution
	conforming to set usage, procedure, or discipline