Denigration

[L. denigratio.]

1. The act of making black. Boyle.

2. Fig.: A blackening; defamation.

The vigorous denigration of science.

noun

1. The expression of injurious, malicious statements about someone: aspersion, calumniation, calumny, character assassination, defamation, detraction, scandal, slander, traducement, vilification. Law libel. See attack/defend, crimes, law.
2. The act or an instance of belittling: belittlement, deprecation, depreciation, derogation, detraction, disparagement, minimization. See attack/defend, show/hide.

The noun has 3 meanings:

Meaning #1: a belittling comment
  Synonym: belittling

Meaning #2: an abusive attack on a person's character or good name
  Synonyms: aspersion, calumny, slander, defamation

Meaning #3: the act of expressing disapproval (especially of yourself)
  Synonym: deprecation