Needlessness is a synonym of unnecessity.
As nouns the difference between unnecessity and needlessness
is that unnecessity is needlessness while needlessness is the state or characteristic of being needless.
unnecessity
English
Noun
(unnecessities)
(lb) needlessness
something that is (l)
needlessness
English
Noun
(es)
the state or characteristic of being needless
Synonyms
* gratuitousness, unnecessariness, unnecessity