Source : Webster's Revised Unabridged Dictionary (1913)

Fag \Fag\, v. i. [imp. & p. p. {Fagged}; p. pr. & vb. n.
   {Fagging}.] [Cf. LG. fakk wearied, weary, vaak slumber,
   drowsiness, OFries. fai, equiv. to f[=a]ch devoted to death,
   OS. f?gi, OHG. feigi, G. feig, feige, cowardly, Icel. feigr
   fated to die, AS. f?ge, Scot. faik, to fail, stop, lower the
   price; or perh. the same word as E. flag to droop.]
   1. To become weary; to tire.

            Creighton withheld his force till the Italian began
            to fag.                               --G.
                                                  Mackenzie.

   2. To labor to wearness; to work hard; to drudge.

            Read, fag, and subdue this chapter.   --Coleridge.

   3. To act as a fag, or perform menial services or drudgery,
      for another, as in some English schools.

   {To fag out}, to become untwisted or frayed, as the end of a
      rope, or the edge of canvas.