谗言讪语chán yán shàn yǔ

satirize and ridicule(/sneer at/deride/jeer)
❍ 我们也错看了这猴子了，平时间～，与他耍子，怎知他有这般真实本事。(《西游记》四十六)We also made wrong judgment on this monkey. Normally we satirize and sneer at him in a playful manner. None of us has expected that he has got such real skills.