From Li Baojia's late-Qing novel 《官场现形记》 (Officialdom Unmasked), chapter 47: 卜知府阳奉阴违,也就奈何他不得 — 'Prefect Bu complied openly and defied secretly; there was nothing one could do to him.' The 阳/阴 pair is the classical 'bright/dark,' 'public/private.'
culture
A core bureaucratic-culture vice in Chinese political language — a recurring target of anti-corruption campaigns, Party rectification, and imperial censor memorials alike. The flip side of 表里如一 (inside and outside match).