IR vs administrative body

IR and administrative body both are nouns.

Word	Noun	Adjective	Verb	Adverb
IR	Yes	No	No	No
administrative body	Yes	No	No	No

As nouns, administrative body is a hypernym of IR; that is, administrative body is a word with a broader meaning than IR:

IR: a board of the British government that administers and collects major direct taxes
administrative body: a unit with administrative responsibilities

Other hypernyms of IR include administrative unit.

IR (noun)	administrative body (noun)
a board of the British government that administers and collects major direct taxes	a unit with administrative responsibilities