officialdom vs organisation

officialdom and organisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
officialdom	Yes	No	No	No
organisation	Yes	No	No	No

As nouns, organisation is a hypernym of officialdom; that is, organisation is a word with a broader meaning than officialdom:

officialdom: people elected or appointed to administer a government
organisation: the persons (or committees or departments etc.) who make up a body for the purpose of administering something

Other hypernyms of officialdom include administration, brass, establishment, governance, governing body, organization.

officialdom (noun)	organisation (noun)
people elected or appointed to administer a government	the act of organizing a business or an activity related to a business
	the activity or result of distributing or disposing persons or things properly or methodically
	the act of forming or establishing something
	an ordered manner; orderliness by virtue of being methodical and well organized
	an organized structure for arranging or classifying
	a group of people who work together
	the persons (or committees or departments etc.) who make up a body for the purpose of administering something