The Collaborative International Dictionary of English v.0.48:

Jigger \Jig"ger\ (j[i^]g"g[~e]r), n. [A corrupt. of chigre.]
   1. (Zool.) A species of flea (Tunga penetrans, or
      Sarcopsylla penetrans, or Pulex penetrans), which
      burrows beneath the skin; called also jigger flea. See
      Chigoe.
      [1913 Webster]

   2. (Zool.) Any one of several species of small red mites
      (esp. Tetranychus irritans and Tetranychus Americanus)
      of the family Trombiculidae, which, in the larval or
      leptus stage, burrow beneath the skin of man and various
      animals, causing great annoyance. Also called chigger.
      [Southern U. S.]
      [Webster 1913 Suppl. +PJC]

The Collaborative International Dictionary of English v.0.48:

Jigger \Jig"ger\, v. t. [Cf. Jiggle.]
   To move, send, or drive with a jerk; to jerk; also, to drive
   or send over with a jerk, as a golf ball.

         He could jigger the ball o'er a steeple tall as most
         men would jigger a cop.                  --Harper's
                                                  Mag.
   [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Jigger \Jig"ger\, n. [See Jig, n. & v.]
   1. One who, or that which, jigs; specifically, a miner who
      sorts or cleans ore by the process of jigging; also, the
      sieve used in jigging.
      [1913 Webster]

   2. (Pottery)
      (a) A horizontal table carrying a revolving mold, on which
          earthen vessels are shaped by rapid motion; a potter's
          wheel.
      (b) A template or tool by which vessels are shaped on a
          potter's wheel.
          [1913 Webster]

   3. (Naut.)
      (a) A light tackle, consisting of a double and single
          block and the fall, used for various purposes, as to
          increase the purchase on a topsail sheet in hauling it
          home; the watch tackle. --Totten.
      (b) A small fishing vessel, rigged like a yawl. [New Eng.]
      (c) A supplementary sail. See Dandy, n., 2
      (b) .
          [1913 Webster]

   4. A pendulum rolling machine for slicking or graining
      leather; same as Jack, 4
      (i) .
          [1913 Webster]

   5. A small glass or measuring vessel holding 11/2 ounces (45
      ml), used mostly for measuring liquor or drinking whiskey;
      also, the quantity of liquid held in a jigger.
      [PJC]

   6. A thingamajig. [Colloq.]
      [PJC]

   Jigger mast. (Naut.)
      (a) The after mast of a four-masted vessel.
      (b) The small mast set at the stern of a yawl-rigged boat.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dandy \Dan"dy\ (d[a^]n"d[y^]), n.; pl. Dandies
   (d[a^]n"d[i^]z). [Cf. F. dandin, ninny, silly fellow,
   dandiner to waddle, to play the fool; prob. allied to E.
   dandle. Senses 2 & 3 are of uncertain etymology.]
   1. One who affects special finery or gives undue attention to
      dress; a fop; a coxcomb.
      [1913 Webster]

   2. (Naut.)
      (a) A sloop or cutter with a jigger on which a lugsail is
          set.
      (b) A small sail carried at or near the stern of small
          boats; -- called also jigger, and mizzen.
          [1913 Webster]

   3. A dandy roller. See below.
      [1913 Webster]

   Dandy brush, a yard whalebone brush.

   Dandy fever. See Dengue.

   Dandy line, a kind of fishing line to which are attached
      several crosspieces of whalebone which carry a hook at
      each end.

   Dandy roller, a roller sieve used in machines for making
      paper, to press out water from the pulp, and set the
      paper. Dandy-cock

The Collaborative International Dictionary of English v.0.48:

Chigoe \Chig"oe\, Chigre \Chig"re\, n. [Cf. F. chigue, perh. fr.
   Catalan chic small, Sp. chico; or of Peruvian origin.]
   (Zool.)
   A species of flea (Tunga penetrans, formerly Pulex
   penetrans), common in the West Indies and South America,
   which often attacks the feet or any exposed part of the human
   body, and burrowing beneath the skin produces great
   irritation. When the female is allowed to remain and breed,
   troublesome sores result, which are sometimes dangerous. See
   Jigger. [Written also chegre, chegoe, chique,
   chigger, jigger.]
   [1913 Webster]

   Note: The name is sometimes erroneously given to certain
         mites or ticks having similar habits.
         [1913 Webster]

WordNet (r) 3.0 (2006):

jigger
    n 1: a small glass adequate to hold a single swallow of whiskey
         [syn: shot glass, jigger, pony]
    2: any small mast on a sailing vessel; especially the mizzenmast
       of a yawl [syn: jiggermast, jigger]
    3: larval mite that sucks the blood of vertebrates including
       human beings causing intense irritation [syn: harvest mite,
       chigger, jigger, redbug]

Moby Thesaurus II by Grady Ward, 1.0:

119 Moby Thesaurus words for "jigger":
   affair, angler, article, artifact, cat flea, chigoe, cockroach,
   concern, crab, dibber, dibbler, dingus, dofunny, dog flea,
   dohickey, dojigger, dojiggy, domajig, domajigger, doodad, dowhacky,
   draft, dram, drench, drift netter, drifter, drink, drop, eppes,
   etwas, fidget, fisher, fisherman, flea, flick, flip, flirt,
   flounce, flumadiddle, gadget, gargle, gigamaree, gimmick, gizmo,
   grayback, guddler, guzzle, have the fidgets, hickey, hitch,
   hootenanny, hootmalalie, itch, jacker, jerk, jig, jigget, jiggle,
   jog, joggle, jolt, libation, louse, material thing, mite, nip, nit,
   object, parasite, peg, piscator, piscatorialist, piscatorian,
   pluck, potation, potion, pull, quelque chose, red bug, roach,
   round, round of drinks, sand flea, shot, sip, snake, snatch,
   snifter, snort, something, spot, suck, sup, swig, swill,
   the compleat angler, thing, thingum, thingumabob, thingumadad,
   thingumadoodle, thingumajig, thingumajigger, thingumaree,
   thingummy, trawler, troller, tweak, twitch, vellicate, vermin,
   weevil, wet, whaler, whatchy, widget, wrench, yank, yerk