a person who destroys or ruins or lays waste to; "a
destroyer of the environment"; "jealousy was his undoer"; "uprooters of gravestones" Synonym(s):destroyer, ruiner, undoer, waster, uprooter
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
Ruiner \Ru"in*er\, n.
One who, or that which, ruins.