不成文 bù chéng wén 🔊 unwritten (rule) + Keep this word Meanings bù chéng wén unwritten (rule) Its characters 不bùnot; noHSK 1成chéngto succeedHSK 6文wénlanguageHSK 7–9 Words with 不成文 不成文法 bù chéng wén fǎ unwritten law