一个冠冕堂皇的借口一个自欺欺人的理由
[yī gè guān miăn táng huáng de jiè kŏu yī gè zì qī qī rén de lĭ yóu]
It implies having grand-sounding excuses and self-deceptive reasons. The owner of this name may want to express the idea of deceiving oneself into accepting flimsy pretenses as valid reasons for some actions, often in a somewhat sarcastic manner.