The Collaborative International Dictionary of English v.0.48:

Shack \Shack\, v. t. [Prov. E., to shake, to shed. See Shake.]
   1. To shed or fall, as corn or grain at harvest. [Prov. Eng.]
      --Grose.
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   2. To feed in stubble, or upon waste corn. [Prov. Eng.]
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   3. To wander as a vagabond or a tramp. [Prev.Eng.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shack \Shack\, n. [Cf. Shack, v. i.]
   a small simple dwelling, usually having only one room and of
   flimsy construction; a hut; a shanty; a cabin. [Colloq.]

The Collaborative International Dictionary of English v.0.48:

Shack \Shack\, n. [Cf. Scot. shag refuse of barley or oats.]
   1. The grain left after harvest or gleaning; also, nuts which
      have fallen to the ground. [Prov. Eng.]
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   2. Liberty of winter pasturage. [Prov. Eng.]
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   3. A shiftless fellow; a low, itinerant beggar; a vagabond; a
      tramp. [Prov. Eng. & Colloq. U.S.] --Forby.
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            All the poor old shacks about the town found a
            friend in Deacon Marble.              --H. W.
                                                  Beecher.
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            These miserable shacks are so low that their
            occupants cannot stand erect.         --D. C.
                                                  Worcester.
      [Webster 1913 Suppl.]

   Common of shack (Eng.Law), the right of persons occupying
      lands lying together in the same common field to turn out
      their cattle to range in it after harvest. --Cowell.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shack
    n 1: small crude shelter used as a dwelling [syn: hovel,
         hut, hutch, shack, shanty]
    v 1: make one's home in a particular place or community; "may
         parents reside in Florida" [syn: reside, shack,
         domicile, domiciliate]
    2: move, proceed, or walk draggingly or slowly; "John trailed
       behind his class mates"; "The Mercedes trailed behind the
       horse cart" [syn: trail, shack]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "shack":
   Nissen hut, Quonset hut, booth, box, bum, cabin, caboose, camp,
   cot, cottage, crib, derelict, drifter, dump, floater, garrote,
   gatehouse, hobo, hovel, hut, hutch, kiosk, lean-to, lodge,
   outbuilding, outhouse, pavilion, sentry box, shanty, shed, stall,
   street arab, tollbooth, tollhouse, tramp, traveler