[ApplegateRanch]

I can't wait to hear CBS & Dan Rather reveal their "unimpeachable" source.

Anybody not holding high public office is "unimpeachable".

An "absolutely credible, scrupulously honest" source is something else altogether.

[rolling_stone]

actually impeachable also goes to credibility or criminality, both may be applicable here:


1 a: to bring an accusation against b : to charge with a crime or misdemeanor; specifically : to charge (a public official) before a competent tribunal with misconduct in office
2 : to cast doubt on; especially : to challenge the credibility or validity of impeach the testimony of a witness 3
3 : to remove from office especially for misconduct