He was the kind of person who would flatter you to your face, and then slander you behind your back.

他是那种当面胁肩谄笑。背地里造谣中伤的人。

《新英汉大辞典》

When Boeing tried to distract attention from this flop by announcing a near-supersonic long-haul jet dubbed the sonic Cruiser, it fell even flatter on its face.

此时，为了转移人们对此事件的注意力，波音宣布高亚音速巡航机，甚至夸大其辞。

youdao

Thus to see studies that lay the ground for flatter incomes because of hardwired human jealousy are, well, dubious on the face of it.

FORBES: The Politics Of Jealousy