briefness vs length

briefness and length both are nouns.

Word	Noun	Adjective	Verb	Adverb
briefness	Yes	No	No	No
length	Yes	No	No	No

As nouns, length is a hypernym of briefness; that is, length is a word with a broader meaning than briefness:

Other hypernyms of briefness include duration.

briefness (noun)	length (noun)
the attribute of being brief or fleeting	a section of something that is long and narrow
the temporal property of being very short	the linear extent in space from one end to the other; the longest dimension of something that is fixed in place
	continuance in time
	the property of being the extent of something from beginning to end
	size of the gap between two places