lengthiness vs length

lengthiness and length both are nouns.

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

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

Other hypernyms of lengthiness include duration.

lengthiness (noun)	length (noun)
amount or degree or range to which something extends	a section of something that is long and narrow
the consequence of being lengthened in duration	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