uncommonness

from WordNet (r) 3.0 (2006)

uncommonness
    n 1: extraordinariness as a consequence of being marked by an
         uncommon or superlative quality
    2: extraordinariness as a consequence of being rare and seldom
       encountered [ant: {commonness}, {commonplaceness},
       {everydayness}]

from The Collaborative International Dictionary of English v.0.48

Uncommon \Un*com"mon\, a.
   Not common; unusual; infrequent; rare; hence, remarkable;
   strange; as, an uncommon season; an uncommon degree of cold
   or heat; uncommon courage.
   [1913 Webster]

   Syn: Rare; scarce; infrequent; unwonted.
        [1913 Webster] -- {Un*com"mon*ly}, adv. --
        {Un*com"mon*ness}, n.
        [1913 Webster]