[syn: graveness, gravity, sobriety, soberness, somberness, sombreness]
The Collaborative International Dictionary of English v.0.48:
Somberness \Som"ber*ness\, Sombreness \Som"bre*ness\, n.
   The quality or state of being somber; gloominess.
   [1913 Webster]
WordNet (r) 3.0 (2006):
sombreness
    n 1: a state of partial or total darkness; "he struck a match to
         dispel the gloom" [syn: gloom, somberness,
         sombreness]
    2: a feeling of melancholy apprehension [syn: gloom,
       gloominess, somberness, sombreness]
    3: a manner that is serious and solemn [syn: graveness,
       gravity, sobriety, soberness, somberness,
       sombreness]