lebensraum vs elbow room

lebensraum and elbow room both are nouns.

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

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

lebensraum: space sought for occupation by a nation whose population is expanding
elbow room: space for movement

Other hypernyms of lebensraum include room, way.

lebensraum (noun)	elbow room (noun)
space sought for occupation by a nation whose population is expanding	space for movement