adjective

tending to bring harm to a reputation.

allegations of discreditable conduct

dishonourable,reprehensible,shameful,deplorable,disgraceful,disreputable,blameworthy,culpable,wrong,bad,ignoble,shabby,objectionable,regrettable,unfortunate,indefensible,unjustifiable,unacceptable,unworthy,remiss,exceptionable