The Collaborative International Dictionary of English v.0.48:

Fag \Fag\ (f[a^]g) n.
   1. A knot or coarse part in cloth; a flaw. [Obs.]
      [1913 Webster]

   2. A cigarette. [slang]
      [PJC]

   3. A fag end in a cloth.
      [PJC]

   4. A drudge.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

fag \fag\ (f[a^]g), n.
   A male homosexual; -- always used disparagingly and
   considered offensive. Shortened form of faggot. [Slang,
   disparaging.]

   Syn: faggot.
        [PJC]

The Collaborative International Dictionary of English v.0.48:

Fag \Fag\, v. i. [imp. & p. p. Fagged (f[a^]gd); p. pr. & vb.
   n. Fagging (f[a^]g"g[i^]ng).] [Cf. LG. fakk wearied, weary,
   vaak slumber, drowsiness, OFries. fai, equiv. to f[=a]ch
   devoted to death, OS. f[=e]gi, OHG. feigi, G. feig, feige,
   cowardly, Icel. feigr fated to die, AS. f[=ae]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.
      [1913 Webster]

            Creighton withheld his force till the Italian began
            to fag.                               --G.
                                                  Mackenzie.
      [1913 Webster]

   2. To labor to wearness; to work hard; to drudge.
      [1913 Webster]

            Read, fag, and subdue this chapter.   --Coleridge.
      [1913 Webster]

   3. To act as a fag, or perform menial services or drudgery,
      for another, as in some English schools.
      [1913 Webster]

   To fag out, to become untwisted or frayed, as the end of a
      rope, or the edge of canvas.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fag \Fag\, v. t.
   1. To tire by labor; to exhaust; as, he was almost fagged
      out.
      [1913 Webster]

   2. Anything that fatigues. [R.]
      [1913 Webster]

            It is such a fag, I came back tired to death. --Miss
                                                  Austen.
      [1913 Webster]

   Brain fag. (Med.) See Cerebropathy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fag
    n 1: offensive term for an openly homosexual man [syn: fagot,
         faggot, fag, fairy, nance, pansy, queen,
         queer, poof, poove, pouf]
    2: finely ground tobacco wrapped in paper; for smoking [syn:
       cigarette, cigaret, coffin nail, butt, fag]
    v 1: act as a servant for older boys, in British public schools
    2: work hard; "She was digging away at her math homework";
       "Lexicographers drudge all day long" [syn: labor, labour,
       toil, fag, travail, grind, drudge, dig, moil]
    3: exhaust or get tired through overuse or great strain or
       stress; "We wore ourselves out on this hike" [syn: tire,
       wear upon, tire out, wear, weary, jade, wear out,
       outwear, wear down, fag out, fag, fatigue] [ant:
       freshen, refresh, refreshen]