[zhǐ fù wéi hūn]   

指    腹    为    婚    在怀孕时就为子女定下婚约。

“指腹为婚”是我国古代的一种特殊嫁娶形式。所谓“指腹婚”，就是指子女尚在娘肚子里，父母亲就给指定了婚姻。

Propose a marriage by pointing to the stomach -- an old practice of marriage had been engaged to each other before they were born

指日高升    指空话空    指山说磨    指山卖磨    指手画脚