Beware

• POS: Verb (usu participle)
• HYPHEN: be=ware

CIDE DICTIONARY

Beware, v. i. [Be, imperative of verb to be + ware. See Ware, Wary.].

•  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 !"  [1913 Webster]

  "Beware the awful avalanche."  [1913 Webster]
•  To have a special regard; to heed.  [1913 Webster]

  " 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]

  "Behold, I send an Angel before thee. . . . Beware of him, and obey his voice."  [1913 Webster]

Beware, v. t. 

 To avoid; to take care of; to have a care for.  Shak.  [1913 Webster]
"To wish them beware the son."  [1913 Webster]

OXFORD DICTIONARY

Beware, v. (only in imper. or infin.)
1 intr. (often foll. by of, or that, lest, etc. + clause) be cautious, take heed (beware of the dog; told us to beware; beware that you don't fall).
2 tr. be cautious of (beware the Ides of March).

Etymology

BE + WARE(3)

ROGET THESAURUS

Beware

Warning

VB warn, caution, forewarn, prewarn, admonish, premonish, give notice, give warning, dehort, menace, put on one's guard, sound the alarm, croak, beware, ware, take warning, take heed at one's peril, keep watch and ward.