Noah Webster's New International Dictionary of the English Language

1. (v.) To destroy confidence or trust in; to cause disbelief in the accuracy of; as, to discredit a source.

2. (n.) Hence, some degree of dishonor or disesteem; ill repute; reproach; -- applied to persons or things.

3. (v. t.) To refuse credence to; not to accept as true; to disbelieve; as, the report is discredited.

4. (v. t.) To deprive of credibility

5. (v. t.) To deprive of credit or good repute; to bring reproach upon; to make less reputable; to disgrace.