lengthiness vs prolongation

lengthiness and prolongation both are nouns.

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

As nouns, lengthiness and prolongation are synonyms defined as:

lengthiness and prolongation: amount or degree or range to which something extends

Other synonyms of lengthiness include extension.

As nouns, lengthiness and prolongation are synonyms defined as:

lengthiness and prolongation: the consequence of being lengthened in duration

Other synonyms of lengthiness include continuation, protraction.

lengthiness (noun)	prolongation (noun)
amount or degree or range to which something extends	the act of prolonging something
the consequence of being lengthened in duration	amount or degree or range to which something extends
	the consequence of being lengthened in duration