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]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "ruination":
   bane, bankruptcy, bloodbath, blue ruin, breakage, breakdown,
   breakup, carnage, collapse, confusion, consumption, crack-up,
   crippling, damage, damnation, decimation, depredation, desolation,
   despoilment, despoliation, destroyer, destruction, detriment,
   devastation, dilapidation, disablement, disintegration,
   disorganization, disrepair, disruption, dissolution, encroachment,
   harm, havoc, hecatomb, hobbling, holocaust, hurt, hurting,
   impairment, incapacitation, infringement, injury, inroad, loss,
   maiming, mayhem, mischief, mutilation, perdition, ravage, ruin,
   ruinousness, sabotage, scathe, shambles, sickening, slaughter,
   spoiling, spoliation, undoing, vandalism, waste, weakening, wrack,
   wrack and ruin, wreck