discredit

[1]	detract , disparage , defame , dishonour , disgrace , degrade , bring into disfavour/disrepute , deprecate , demean , lower , devalue , depreciate , devaluate , belittle , diminish , reduce , slur , slander , vilify , calumniate , sully , smear , blacken , taint , tarnish , besmirch , smirch , stigmatize , asperse , malign , libel
[2]	disbelieve , deny , dispute , doubt , question , raise doubts about , distrust , mistrust , give no credit/credence to
[3]	disprove , disgrace , reject , refute , invalidate , mock , ridicule
[4]	disbelieve

[1]	disrepute
[2]	dishonour , degradation , disfavour , disrepute , ill repute , disgrace , ignominy , infamy , odium , stigma , shame , smear , slur , scandal , obloquy , opprobrium , humiliation
[3]	damage , harm , reflection , slur , aspersion , slander , defamation , blot , brand , tarnish , blemish , taint
[4]	doubt , scepticism , dubiousness , doubtfulness , qualm , scruple , question , incredulity , suspicion , distrust , mistrust