forewarn a person of the danger
Every year, Bangladeshi government takes strong measures to stop cheating and carries out a massive media campaign to forewarn students through print and television.
We are missing a golden opportunity to forewarn new parents of the challenges they might face once their baby arrives.
But I will forewarn you whom ye shall fear: fear him, which after he hath killed hath power to cast into hell; yea, I say unto you, fear him.
forewarn a person that it may be dangerous to swim here
The fishermen is forewarn of the oncoming of the storm