Source : Webster's Revised Unabridged Dictionary (1913)

Soberness \So"ber*ness\, n.
   The quality or state of being sober.

Source : WordNet®

soberness
     n 1: the state of being sober [syn: {sobriety}] [ant: {drunkenness}]
     2: a manner that is serious and solemn [syn: {graveness}, {gravity},
         {sobriety}, {somberness}]