Source : Webster's Revised Unabridged Dictionary (1913)

Backbite \Back"bite`\, v. i. [2nd back, n., + bite]
   To wound by clandestine detraction; to censure meanly or
   spitefully (an absent person); to slander or speak evil of
   (one absent). --Spenser.

Backbite \Back"bite`\, v. i.
   To censure or revile the absent.

         They are arrant knaves, and will backbite. --Shak.

Source : WordNet®

backbite
     v : say mean things [syn: {bitch}]
     [also: {backbitten}, {backbit}]