lost credibility

• discreditedProven unworthy of trust
• tarnishedOxidized and discolored
• reputationCollective opinion of someone
• scandalDisgraceful public affair
• liarOne who speaks falsely

exposed · disgraced · fallen · shamed · untrustworthy · fraud · betrayed · ruined · doubted · questioned · dishonored · debunked · humiliated · fake · phony · damaged · suspect · unreliable