a gross fabrication
Xiang Bi is a Chinese idiom. The Pinyin is Xi à NGB à x à g à u, which means Xiang Bi, facing the wall. That is, facing the wall, made out of thin air. Metaphor is not based on facts. It comes from preface of Shuowen Jiezi.
The origin of Idioms
The preface of Shuowen Jiezi written by Xu Shen of Han Dynasty: "the common people are not Zi. They think that they are curious, so they are more cunning. They make up unknown books in the countryside, and they often act in disorder to shine on the world."
Analysis of Idioms
Synonym: fictitious to the wall and fictitious to the face
Idiom usage
As predicate, object and attribute, it refers to imagination and fabrication
Examples
It seems that there is a reason for it, and it is reasonable to say so. On Yan Fu's salvation
a gross fabrication
try to carve a swan and at least you 'll get a duck - kè hú chéng wù
suffer great agonies of the mind - chóu cháng bǎi jié
to do good and dissuade him from doing evil - quàn shàn jiè è