离经叛道（離經叛道）　

◎ 离经叛道 líjīng-pàndào

[depart from the classics and rebel against orthodoxy; be guilty of heterodoxy; be heretical and deviate from the true teachings] 背离正道;违反正统的经典道德规范

且本官志大言浮,离经叛道。——《元曲选外编·贬黄州》