administrative body vs IR

administrative body and IR both are nouns.

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

As nouns, IR is a hyponym of administrative body; that is, IR is a word with a more specific, narrower meaning than administrative body:

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

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