The Collaborative International Dictionary of English v.0.48:

Fib \Fib\, v. i. [imp. & p. p. Fibbed; p. pr. & vb. n.
   Fibbing.]
   To speak falsely. [Colloq.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

fibbing
    n 1: a trivial act of lying or being deliberately unclear [syn:
         fibbing, paltering]