Literally, to restrain or guard one’s self from. Hence, to regard with caution; to restrain one’s self from anything that may be dangerous, injurious or improper; to avoid; to take care; followed by of before the thing that is to be avoided. Beware of all, but more beware of man. Beware of false prophets; beware of the leaven of the Pharisees; beware of the concision.

To have a special regard to. Behold, I send an angel before thee--beware of him, and obey his voice. Exodus 23:20, 21. This word though here admitted as a verb, from the Saxon, is rarely used as a verb in fact; or if a verb, is now never used except in the imperative mode. It is a compound of be and the Old Eng. ware, now wary. Be wary of danger. Hence it cannot be used with did, like a regular verb, nor with be, in any of its inflections, he is beware; for this would be to use the substantive verb twice before ware and wary, is and be. Ben Jonson however has used the word in the third person. He bewares to act. But it has no past tense or participle, and therefore, if admitted as a verb, it is defective, and used only in the imperative mode, or after an auxiliary. We must beware of excess.