idiom · To cross the sea by a trick; to use a bold stratagem to deceive others in order to achieve a goal.

他用瞒天过海之计，顺利地避开了敌人的搜查。

idiom · To achieve one's aim by underhanded or sneaky means.

他企图用瞒天过海的手法，私自将公司的资金转移走。