The Collaborative International Dictionary of English v.0.48:
Discredit \Dis*cred"it\, v. t. [imp. & p. p. Discredited; p.
pr. & vb. n. Discrediting.] [Cf. F. discr['e]diter.]
1. To refuse credence to; not to accept as true; to
disbelieve; as, the report is discredited.
2. To deprive of credibility; to destroy confidence or trust
in; to cause disbelief in the accuracy or authority of.
An occasion might be given to the . . . papists of
discrediting our common English Bible. --Strype.
2. To deprive of credit or good repute; to bring reproach
upon; to make less reputable; to disgrace.
He. . . least discredits his travels who returns the
same man he went. --Sir H.