unobtrusiveness

from WordNet (r) 3.0 (2006)

unobtrusiveness
    n 1: the quality of not sticking out in an unwelcome way [ant:
         {obtrusiveness}]

from The Collaborative International Dictionary of English v.0.48

Unobtrusive \Un`ob*tru"sive\, a.
   Not obtrusive; not presuming; modest. -- {Un`ob*tru"sive*ly},
   adv. -- {Un`ob*tru"sive*ness}, n.
   [1913 Webster]