The Collaborative International Dictionary of English v.0.48:

Baccare \Bac*ca"re\, Backare \Bac*ka"re\, interj.
   Stand back! give place! -- a cant word of the Elizabethan
   writers, probably in ridicule of some person who pretended to
   a knowledge of Latin which he did not possess.
   [1913 Webster]

         Baccare! you are marvelous forward.      --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Backare \Bac*ka"re\, interj.
   Same as Baccare.
   [1913 Webster]