be ‧ ware /bɪˈweə $ -ˈwer/ BrE AmE verb [intransitive, transitive only in imperative and infinitive]
[ Date: 1200-1300 ; Origin: be + ware 'careful' (11-19 centuries) (from Old English wær ) ]
used to warn someone to be careful because something is dangerous
beware of
Beware of the dog!
beware of doing something
They should beware of making hasty decisions.
Police warned drivers to beware.