Definitions of discredit:

• noun:   the state of being held in low esteem

  Example: "Your actions will bring discredit to your name"

• verb:   cause to be distrusted or disbelieved

  Example: "The paper discredited the politician with its nasty commentary"

• verb:   damage the reputation of

  Example: "This newspaper story discredits the politicians"

• verb:   reject as false; refuse to accept