'Beware' definitions:

Definition of 'beware'

verb

Be on one's guard; be cautious or wary about; be alert to; "Beware of telephone salesmen" [syn: beware, mind]

From: GCIDE

Beware \Be*ware"\, v. i. [Be, imperative of verb to be + ware. See Ware, Wary.]
1. To be on one's guard; to be cautious; to take care; -- commonly followed by of or lest before the thing that is to be avoided. [1913 Webster]
Beware of all, but most beware of man ! --Pope. [1913 Webster]
Beware the awful avalanche. --Longfellow. [1913 Webster]
2. To have a special regard; to heed. [Obs.] [1913 Webster]
Behold, I send an Angel before thee. . . . Beware of him, and obey his voice. --Ex. xxiii.
20, 21. [1913 Webster]
Note: This word is a compound from be and the Old English ware, now wary, which is an adjective. "Be ye war of false prophetis." --Wyclif, Matt. vii. 15. It is used commonly in the imperative and infinitive modes, and with such auxiliaries (shall, should, must, etc.) as go with the infinitive. [1913 Webster]

From: GCIDE

Beware \Be*ware"\ (b[-e]*w[^a]r"), v. t. To avoid; to take care of; to have a care for. [Obs.] "Priest, beware your beard." --Shak. [1913 Webster]
To wish them beware the son. --Milton. [1913 Webster]