(physics) Initialism of focused ion beam. / (Wisconsin, derogatory, offensive) Initialism of fucking Illinois bastard.

(informal) A lie, especially one that is more or less inconsequential. / (informal, rare) A liar.

(informal, intransitive) To lie, especially more or less inconsequentially.

(medicine, informal) The fibula.

(archaic, thieves' cant, boxing) To punch, especially a series of punches in rapid succession; to beat; to hit; to strike.

(neologism) A kind of experimental poem where the number of syllables in each line is the next succeeding Fibonacci number.

present participle of fib

(informal) The telling of a lie. / (archaic, boxing) Repeatedly striking an opponent's head while holding them in a headlock; a pummelling; a drubbing; a beating.

simple past tense and past participle of fib

(medicine) Abbreviation of atrial fibrillation; also A-fib.