The Collaborative International Dictionary of English v.0.48:

Feather \Feath"er\, v. t. [imp. & p. p. Feathered; p. pr. &
   vb. n. Feathering.]
   1. To furnish with a feather or feathers, as an arrow or a
      cap.
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            An eagle had the ill hap to be struck with an arrow
            feathered from her own wing.          --L'Estrange.
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   2. To adorn, as with feathers; to fringe.
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            A few birches and oaks still feathered the narrow
            ravines.                              --Sir W.
                                                  Scott.
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   3. To render light as a feather; to give wings to.[R.]
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            The Polonian story perhaps may feather some tedious
            hours.                                --Loveday.
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   4. To enrich; to exalt; to benefit.
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            They stuck not to say that the king cared not to
            plume his nobility and people to feather himself.
                                                  --Bacon.
      --Dryden.
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   5. To tread, as a cock. --Dryden.
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   To feather one's nest, to provide for one's self especially
      from property belonging to another, confided to one's
      care; -- an expression taken from the practice of birds
      which collect feathers for the lining of their nests.

   To feather an oar (Naut), to turn it when it leaves the
      water so that the blade will be horizontal and offer the
      least resistance to air while reaching for another stroke.


   To tar and feather a person, to smear him with tar and
      cover him with feathers, as a punishment or an indignity.
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The Collaborative International Dictionary of English v.0.48:

Feather \Feath"er\, v. i.
   1. To grow or form feathers; to become feathered; -- often
      with out; as, the birds are feathering out.
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   2. To curdle when poured into another liquid, and float about
      in little flakes or "feathers;" as, the cream feathers.
      [Colloq.]
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   3. To turn to a horizontal plane; -- said of oars.
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            The feathering oar returns the gleam. --Tickell.
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            Stopping his sculls in the air to feather
            accurately.                           --Macmillan's
                                                  Mag.
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   4. To have the appearance of a feather or of feathers; to be
      or to appear in feathery form.
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            A clump of ancient cedars feathering in evergreen
            beauty down to the ground.            --Warren.
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            The ripple feathering from her bows.  --Tennyson.
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The Collaborative International Dictionary of English v.0.48:

Feather \Feath"er\ (f[e^][th]"[~e]r), n. [OE. fether, AS.
   fe[eth]er; akin to D. veder, OHG. fedara, G. feder, Icel.
   fj["o][eth]r, Sw. fj[aum]der, Dan. fj[ae]der, Gr. ptero`n
   wing, feather, pe`tesqai to fly, Skr. pattra wing, feather,
   pat to fly, and prob. to L. penna feather, wing. [root]76,
   248. Cf. Pen a feather.]
   1. One of the peculiar dermal appendages, of several kinds,
      belonging to birds, as contour feathers, quills, and down.
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   Note: An ordinary feather consists of the quill or hollow
         basal part of the stem; the shaft or rachis, forming
         the upper, solid part of the stem; the vanes or webs,
         implanted on the rachis and consisting of a series of
         slender lamin[ae] or barbs, which usually bear
         barbules, which in turn usually bear barbicels and
         interlocking hooks by which they are fastened together.
         See Down, Quill, Plumage.

   2. Kind; nature; species; -- from the proverbial phrase,
      "Birds of a feather," that is, of the same species. [R.]
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            I am not of that feather to shake off
            My friend when he must need me.       --Shak.
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   3. The fringe of long hair on the legs of the setter and some
      other dogs.
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   4. A tuft of peculiar, long, frizzly hair on a horse.
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   5. One of the fins or wings on the shaft of an arrow.
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   6. (Mach. & Carp.) A longitudinal strip projecting as a fin
      from an object, to strengthen it, or to enter a channel in
      another object and thereby prevent displacement sidwise
      but permit motion lengthwise; a spline.
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   7. A thin wedge driven between the two semicylindrical parts
      of a divided plug in a hole bored in a stone, to rend the
      stone. --Knight.
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   8. The angular adjustment of an oar or paddle-wheel float,
      with reference to a horizontal axis, as it leaves or
      enters the water.
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   Note: Feather is used adjectively or in combination, meaning
         composed of, or resembling, a feather or feathers; as,
         feather fan, feather-heeled, feather duster.
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   Feather alum (Min.), a hydrous sulphate of alumina,
      resulting from volcanic action, and from the decomposition
      of iron pyrites; -- called also halotrichite. --Ure.

   Feather bed, a bed filled with feathers.

   Feather driver, one who prepares feathers by beating.

   Feather duster, a dusting brush of feathers.

   Feather flower, an artifical flower made of feathers, for
      ladies' headdresses, and other ornamental purposes.

   Feather grass (Bot.), a kind of grass (Stipa pennata)
      which has a long feathery awn rising from one of the
      chaffy scales which inclose the grain.

   Feather maker, one who makes plumes, etc., of feathers,
      real or artificial.

   Feather ore (Min.), a sulphide of antimony and lead,
      sometimes found in capillary forms and like a cobweb, but
      also massive. It is a variety of Jamesonite.

   Feather shot, or Feathered shot (Metal.), copper
      granulated by pouring into cold water. --Raymond.

   Feather spray (Naut.), the spray thrown up, like pairs of
      feathers, by the cutwater of a fast-moving vessel.

   Feather star. (Zool.) See Comatula.

   Feather weight. (Racing)
      (a) Scrupulously exact weight, so that a feather would
          turn the scale, when a jockey is weighed or weighted.
      (b) The lightest weight that can be put on the back of a
          horse in racing. --Youatt.
      (c) In wrestling, boxing, etc., a term applied to the
          lightest of the classes into which contestants are
          divided; -- in contradistinction to light weight,
          middle weight, and heavy weight.

   A feather in the cap an honour, trophy, or mark of
      distinction. [Colloq.]

   To be in full feather, to be in full dress or in one's best
      clothes. [Collog.]

   To be in high feather, to be in high spirits. [Collog.]

   To cut a feather.
      (a) (Naut.) To make the water foam in moving; in allusion
          to the ripple which a ship throws off from her bows.
      (b) To make one's self conspicuous. [Colloq.]

   To show the white feather, to betray cowardice, -- a white
      feather in the tail of a cock being considered an
      indication that he is not of the true game breed.
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WordNet (r) 3.0 (2006):

feather
    n 1: the light horny waterproof structure forming the external
         covering of birds [syn: feather, plume, plumage]
    2: turning an oar parallel to the water between pulls [syn:
       feather, feathering]
    v 1: join tongue and groove, in carpentry
    2: cover or fit with feathers
    3: turn the paddle; in canoeing [syn: feather, square]
    4: turn the oar, while rowing [syn: feather, square]
    5: grow feathers; "The young sparrows are fledging already"
       [syn: fledge, feather]

Moby Thesaurus II by Grady Ward, 1.0:

226 Moby Thesaurus words for "feather":
   a continental, a curse, a damn, a darn, a hoot, air, bagatelle,
   bank, bauble, bead, bean, bejewel, beribbon, bespangle, bibelot,
   bit, blood, blubber, brand, brass farthing, breed, breeze, bubble,
   butter, button, cast, catch a crab, ceil, cent, chaff, character,
   chip, clan, clay, cobweb, color, cork, covert, crab, crest, curio,
   cushion, cut a crab, denomination, description, designation,
   diamond, dip, dough, down, dust, eiderdown, engrave, ether, face,
   fairy, farce, farthing, feather an oar, feather bed, feathers, fig,
   figure, filigree, fill, fishtail, flag, fleabite, fledge, fleece,
   floss, flounce, flower, flue, fluff, foam, folderol, form, fribble,
   frippery, froth, fur, fuzz, garland, gaud, gem, genre, genus,
   gewgaw, gimcrack, give way, gossamer, grain, hackle, hair,
   halfpenny, hill of beans, ilk, illuminate, inlay, interline, jest,
   jewel, joke, kapok, kickshaw, kidney, kin, kind, knickknack,
   knickknackery, label, line, load, loop, lot, mail, make, manner,
   mark, minikin, mockery, mold, molehill, mote, nature, number,
   order, pace, pack, pad, paddle, paint, panache, peppercorn,
   persuasion, phylum, picayune, pillow, pin, pinch of snuff, pinion,
   pinprick, plow, plumage, plume, plumule, plush, ply the oar,
   porpoise, pudding, puff, pull, pull out, pull up, punt, push down,
   putty, quill, race, rap, red cent, ribbon, roll, row, row away,
   row dry, row of pins, rubber, rush, satin, scapular, scull, shape,
   ship oars, shit, shoot, sideslip, silk, skid, sky an oar, snap,
   sneeshing, sort, sou, spangle, species, speculum, spin, spiral,
   sponge, spume, stamp, strain, straw, stripe, stuff, stunt, style,
   swansdown, the like of, the likes of, thistledown, tinsel, topknot,
   toy, tribe, trifle, trinket, triviality, tuft, tuppence, two cents,
   twopence, type, undulate, variety, velvet, wad, wainscot, wax,
   whim-wham, wool, wreathe, yaw, zephyr