Source : Webster's Revised Unabridged Dictionary (1913)

Fib \Fib\, n. [Prob. fr. fable; cf. Prov. E. fibble-fabble
   nonsense.]
   A falsehood; a lie; -- used euphemistically.

         They are very serious; they don't tell fibs. --H.
                                                  James.

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

Fib \Fib\, v. t.
   To tell a fib to. [R.] --De Quincey.

Source : WordNet®

fib
     v : tell a relatively insignificant lie; "Fibbing is not
         acceptable, even if you don't call it lying"
     [also: {fibbing}, {fibbed}]

fib
     n : a trivial lie; "he told a fib about eating his spinach";
         "how can I stop my child from telling stories?" [syn: {story},
          {tale}, {tarradiddle}, {taradiddle}]
     [also: {fibbing}, {fibbed}]