The Collaborative International Dictionary of English v.0.48:

Clog \Clog\ (kl[o^]g), n. [OE. clogge clog, Scot. clag, n., a
   clot, v., to to obstruct, cover with mud or anything
   adhesive; prob. of the same origin as E. clay.]
   1. That which hinders or impedes motion; hence, an
      encumbrance, restraint, or impediment, of any kind.
      [1913 Webster]

            All the ancient, honest, juridical principles and
            institutions of England are so many clogs to check
            and retard the headlong course of violence and
            opression.                            --Burke.
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   2. A weight, as a log or block of wood, attached to a man or
      an animal to hinder motion.
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            As a dog . . . but chance breaks loose,
            And quits his clog.                   --Hudibras.
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            A clog of lead was round my feet.     --Tennyson.
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   3. A shoe, or sandal, intended to protect the feet from wet,
      or to increase the apparent stature, and having,
      therefore, a very thick sole. Cf. Chopine.
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            In France the peasantry goes barefoot; and the
            middle sort . . . makes use of wooden clogs.
                                                  --Harvey.
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   Clog almanac, a primitive kind of almanac or calendar,
      formerly used in England, made by cutting notches and
      figures on the four edges of a clog, or square piece of
      wood, brass, or bone; -- called also a Runic staff, from
      the Runic characters used in the numerical notation.

   Clog dance, a dance performed by a person wearing clogs, or
      thick-soled shoes.

   Clog dancer.
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The Collaborative International Dictionary of English v.0.48:

Clog \Clog\, v. i.
   1. To become clogged; to become loaded or encumbered, as with
      extraneous matter.
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            In working through the bone, the teeth of the saw
            will begin to clog.                   --S. Sharp.
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   2. To coalesce or adhere; to unite in a mass.
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            Move it sometimes with a broom, that the seeds clog
            not together.                         --Evelyn.
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The Collaborative International Dictionary of English v.0.48:

Clog \Clog\, v. t. [imp. & p. p. Clogged (kl[o^]gd); p. pr. &
   vb. n. Clogging.]
   1. To encumber or load, especially with something that
      impedes motion; to hamper.
      [1913 Webster]

            The winds of birds were clogged with ace and snow.
                                                  --Dryden.
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   2. To obstruct so as to hinder motion in or through; to choke
      up; as, to clog a tube or a channel.
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   3. To burden; to trammel; to embarrass; to perplex.
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            The commodities are clogged with impositions.
                                                  --Addison.
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            You 'll rue the time
            That clogs me with this answer.       --Shak.

   Syn: Impede; hinder; obstruct; embarrass; burden; restrain;
        restrict.
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WordNet (r) 3.0 (2006):

clog
    n 1: footwear usually with wooden soles [syn: clog, geta,
         patten, sabot]
    2: any object that acts as a hindrance or obstruction
    3: a dance performed while wearing shoes with wooden soles; has
       heavy stamping steps [syn: clog dance, clog dancing,
       clog]
    v 1: become or cause to become obstructed; "The leaves clog our
         drains in the Fall"; "The water pipe is backed up" [syn:
         clog, choke off, clog up, back up, congest,
         choke, foul] [ant: unclog]
    2: dance a clog dance
    3: impede the motion of, as with a chain or a burden; "horses
       were clogged until they were tamed"
    4: impede with a clog or as if with a clog; "The market is being
       clogged by these operations"; "My mind is constipated today"
       [syn: clog, constipate]
    5: coalesce or unite in a mass; "Blood clots" [syn: clog,
       clot]
    6: fill to excess so that function is impaired; "Fear clogged
       her mind"; "The story was clogged with too many details"
       [syn: clog, overload]

Moby Thesaurus II by Grady Ward, 1.0:

109 Moby Thesaurus words for "clog":
   arrest, bar, barrier, bearing rein, bind, bit, blank wall,
   blind alley, blind gut, block, block up, blockade, blockage,
   bottleneck, brake, bung, caulk, cecum, chain, check, checkrein,
   chink, chock, choke, choke off, choke up, choking, choking off,
   clog up, congest, congestion, constipate, constipation, cork,
   costiveness, countercheck, cover, cul-de-sac, curb, curb bit, dam,
   dam up, damper, dance, dead end, doorstop, drag, drag sail,
   drift anchor, drift sail, drogue, embolism, embolus, encumber,
   fetter, fill, fill up, foot, foul, fox-trot, gorge, hamper,
   holdback, hoof, hop, impasse, impede, impediment, infarct,
   infarction, jam, martingale, obstacle, obstipate, obstipation,
   obstruct, obstruction, pack, pelham, plug, plug up, prance, remora,
   scotch, sea anchor, sealing off, shackle, shake, shimmy, shuffle,
   skip, snaffle, spile, spoke, stanch, stay, stench, stop, stop up,
   stoppage, stopper, stopple, strangulation, stuff, stuff up,
   tap-dance, trammel, trip, waltz