beware
v.v. to be careful or look out for something dangerous. You often see this on signs to warn you about a risk.
v. to be cautious or on one's guard against potential danger or harm. Primarily used in the imperative or as an infinitive; lacks a full range of inflected forms like a past tense.
Beware of the dog when you enter the yard.
Hikers should beware of falling rocks when walking along the base of the cliffs after a heavy rain.
While the investment opportunity appears lucrative on the surface, seasoned traders warn that one must beware of hidden fees that can quickly erode any potential profit margins.
From Middle English bewar, be war, be ware, forms of Middle English ben ware (“to be on one's guard, be vigilant”, literally “be ware”), equivalent to be + ware or be + aware. Compare Old English bewarian.
He bewared of the dangerHe was wary of the dangerBeware is a defective verb and cannot be used in the past tense; use 'was wary of' or 'avoided' instead.