largeness vs breadth

largeness and breadth both are nouns.

Word	Noun	Adjective	Verb	Adverb
largeness	Yes	No	No	No
breadth	Yes	No	No	No

As nouns, largeness and breadth are synonyms defined as:

largeness and breadth: the capacity to understand a broad range of topics

Other synonyms of largeness include comprehensiveness.

largeness (noun)	breadth (noun)
the property of having a relatively great size	the extent of something from side to side
large or extensive in breadth or importance or comprehensiveness	the capacity to understand a broad range of topics
the quality of being pretentious (behaving or speaking in such a manner as to create a false appearance of great importance or worth)
the capacity to understand a broad range of topics