breathing room vs elbow room

breathing room and elbow room both are nouns.

Word	Noun	Adjective	Verb	Adverb
breathing room	Yes	No	No	No
elbow room	Yes	No	No	No

As nouns, elbow room is a hypernym of breathing room; that is, elbow room is a word with a broader meaning than breathing room:

Other hypernyms of breathing room include room, way.

breathing room (noun)	elbow room (noun)
sufficient room for easy breathing or movement	space for movement