ruin

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The state of being physically destroyed, collapsed, or decayed.
• noun The state of being extensively harmed or damaged.
• noun Poverty of bankruptcy.
• noun A destroyed, collapsed, or decayed building or other physical entity.
• noun One that has been extensively damaged or harmed.
• noun A cause of destruction or irreparable harm or loss.
• transitive verb To cause (a building, for example) to be in a destroyed, collapsed, or decayed state.
• transitive verb To harm or damage irreparably.
• transitive verb To reduce to poverty or bankruptcy.

from The Century Dictionary.

• noun The act of falling or tumbling down; violent fall.
• noun A violent or profound change of a thing, such as to unfit it for use, destroy its value, or bring it to an end; overthrow; downfall; collapse; wreck, material or moral: as, the ruin of a government; the ruin of health; financial ruin.
• noun That which promotes injury, decay, or destruction; bane.
• noun That which has undergone overthrow, downfall, or collapse; anything, as a building, in a state of destruction, wreck, or decay; hence, in the plural, the fragments or remains of anything overthrown or destroyed: as, the ruins of former beauty; the ruins of Nineveh.
• noun The state of being ruined, decayed, destroyed, or rendered worthless.
• noun Synonyms Subversion, wreck, shipwreck, prostration.
• To bring to ruin; cause the downfall, overthrow, or collapse of; damage essentially and irreparably; wreck the material or moral well-being of; demolish; subvert; spoil; undo: as, to ruin a city or a government; to ruin commerce; to ruin one's health or reputation.
• Specifically, to bring to financial ruin; reduce to a state of bankruptcy or extreme poverty.
• Synonyms To destroy, overthrow, overturn, overwhelm.
• To impoverish.
• To fall headlong and with violence; rush furiously downward.
• To fall into ruins; run to ruin; fall into decay; be dilapidated.
• To be overwhelmed by loss, failure, suffering, or the like; be brought to misery or poverty.
• To inflict ruin; do irreparable harm.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete The act of falling or tumbling down; fall.
• noun Such a change of anything as destroys it, or entirely defeats its object, or unfits it for use; destruction; overthrow.
• noun That which is fallen down and become worthless from injury or decay; ; especially, in the plural, the remains of a destroyed, dilapidated, or desolate house, fortress, city, or the like.
• noun The state of being dcayed, or of having become ruined or worthless.
• noun That which promotes injury, decay, or destruction.
• transitive verb To bring to ruin; to cause to fall to pieces and decay; to make to perish; to bring to destruction; to bring to poverty or bankruptcy; to impair seriously; to damage essentially; to overthrow.
• intransitive verb rare To fall to ruins; to go to ruin; to become decayed or dilapidated; to perish.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun countable construction withered by time.
• noun uncountable The state of being a ruin, destroyed or decayed.
• noun uncountable Something which leads to serious troubles.
• verb transitive to cause the ruin of.
• verb To destroy or make something no longer be able to be for good use.
• verb To upset or mess up the plans or progress of, or to put into disarray; to spoil.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an irrecoverable state of devastation and destruction
• verb fall into ruin
• noun the process of becoming dilapidated
• verb reduce to ruins
• noun an event that results in destruction
• verb reduce to bankruptcy
• verb destroy or cause to fail
• noun destruction achieved by causing something to be wrecked or ruined
• noun failure that results in a loss of position or reputation
• verb destroy completely; damage irreparably
• verb deprive of virginity
• noun a ruined building