depravation

from The Century Dictionary.

• noun The act of perverting or distorting; perversion; vilification.
• noun The act of making or becoming bad or worse; the act or process of debasement; deterioration.
• noun Depraved or corrupt quality or character; degeneracy; depravity.
• noun A depraved tendency; inclination toward evil or corruption.
• noun Synonyms Depravity, Depravation, deterioration, corruption, vitiation, contamination, debasement. Depravation is especially the act of depraving or the process of becoming depraved; depravity, the state resulting from the act or process. The use of depravation for depravity is uncommon.

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

• noun obsolete Detraction; depreciation.
• noun The act of depraving, or making anything bad; the act of corrupting.
• noun The state of being depraved or degenerated; degeneracy; depravity.
• noun (Med.) Change for the worse; deterioration; morbid perversion.

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

• noun Detraction; depreciation.
• noun The act of depraving, or making anything bad; the act of corrupting.
• noun The state of being depraved or degenerated; degeneracy; depravity.
• noun Change for the worse; deterioration; morbid perversion.

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

• noun moral perversion; impairment of virtue and moral principles