forewarn

forewarn
verb

[with obj.]inform (someone) of a possible future danger or problem
预先警告，事先告诫
he had been forewarned of a coup plot.
他事先已获警告有政变阴谋。

常用词组
forewarned is forearmed

(proverb)prior knowledge of possible dangers or problems gives one a tactical advantage
(谚)凡事预则立；情报有如武装

派生
forewarner
noun