Source : Webster's Revised Unabridged Dictionary (1913)

Flag \Flag\ (fl[a^]g), v. i. [imp. & p. p. {Flagged}; p. pr. &
   vb. n. {Flagging}.] [Cf. Icel. flaka to droop, hang loosely.
   Cf. {Flacker}, {Flag} an ensign.]
   1. To hang loose without stiffness; to bend down, as flexible
      bodies; to be loose, yielding, limp.

            As loose it [the sail] flagged around the mast. --T.
                                                  Moore.

   2. To droop; to grow spiritless; to lose vigor; to languish;
      as, the spirits flag; the streugth flags.

            The pleasures of the town begin to flag. --Swift.

   Syn: To droop; decline; fail; languish; pine.

Flagging \Flag"ging\, n.
   A pavement or sidewalk of flagstones; flagstones,
   collectively.

Flagging \Flag"ging\, a.
   Growing languid, weak, or spiritless; weakening; delaying. --
   {Flag"ging*ly}, adv.

Source : WordNet®

flagging
     adj : weak from exhaustion [syn: {drooping}]

flag
     n 1: emblem usually consisting of a rectangular piece of cloth of
          distinctive design
     2: plants with sword-shaped leaves and erect stalks bearing
        bright-colored flowers composed of three petals and three
        drooping sepals [syn: {iris}, {fleur-de-lis}, {sword lily}]
     3: a rectangular piece of fabric used as a signalling device
        [syn: {signal flag}]
     4: a listing printed in all issues of a newspaper or magazine
        (usually on the editorial page) that gives the name of the
        publication and the names of the editorial staff, etc.
        [syn: {masthead}]
     5: flagpole used to mark the position of the hole on a golf
        green [syn: {pin}]
     6: stratified stone that splits into pieces suitable as paving
        stones [syn: {flagstone}]
     7: a conspicuously marked or shaped tail
     [also: {flagging}, {flagged}]

flag
     v 1: communicate or signal with a flag
     2: provide with a flag; "Flag this file so that I can recognize
        it immediately"
     3: droop, sink, or settle from or as if from pressure or loss
        of tautness [syn: {sag}, {droop}, {swag}]
     4: decorate with flags; "the building was flagged for the
        holiday"
     5: become less intense [syn: {ease up}, {ease off}, {slacken
        off}]
     [also: {flagging}, {flagged}]

flagging
     See {flag}