An Etymological Dictionary of the German Language/Annotated/redlich

by Friedrich Kluge

redlich, adjective, ‘honest, candid,’ from Middle High German rędelîch, ‘eloquent, intelligent, upright, sturdy,’ Old High German rędilîh, ‘intelligent’; allied to Old High German rędia, Middle High German ręde, ‘understanding, account.’ See Rede.