The Collaborative International Dictionary of English v.0.48:

Ruination \Ru`in*a"tion\, n. [LL. ruinatio.]
   The act of ruining, or the state of being ruined.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ruination
    n 1: an irrecoverable state of devastation and destruction; "you
         have brought ruin on this entire family" [syn: ruin,
         ruination]
    2: an event that results in destruction [syn: ruin,
       ruination]
    3: failure that results in a loss of position or reputation
       [syn: downfall, ruin, ruination]
    4: destruction achieved by causing something to be wrecked or
       ruined [syn: laying waste, ruin, ruining, ruination,
       wrecking]