The Collaborative International Dictionary of English v.0.48:

Thick \Thick\ (th[i^]k), a. [Compar. Thicker (-[~e]r); superl.
   Thickest.] [OE. thicke, AS. [thorn]icce; akin to D. dik,
   OS. thikki, OHG. dicchi thick, dense, G. dick thick, Icel.
   [thorn]ykkr, [thorn]j["o]kkr, and probably to Gael. & Ir.
   tiugh. Cf. Tight.]
   1. Measuring in the third dimension other than length and
      breadth, or in general dimension other than length; --
      said of a solid body; as, a timber seven inches thick.
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            Were it as thick as is a branched oak. --Chaucer.
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            My little finger shall be thicker than my father's
            loins.                                --1 Kings xii.
                                                  10.
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   2. Having more depth or extent from one surface to its
      opposite than usual; not thin or slender; as, a thick
      plank; thick cloth; thick paper; thick neck.
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   3. Dense; not thin; inspissated; as, thick vapors. Also used
      figuratively; as, thick darkness.
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            Make the gruel thick and slab.        --Shak.
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   4. Not transparent or clear; hence, turbid, muddy, or misty;
      as, the water of a river is apt to be thick after a rain.
      "In a thick, misty day." --Sir W. Scott.
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   5. Abundant, close, or crowded in space; closely set;
      following in quick succession; frequently recurring.
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            The people were gathered thick together. --Luke xi.
                                                  29.
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            Black was the forest; thick with beech it stood.
                                                  --Dryden.
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   6. Not having due distinction of syllables, or good
      articulation; indistinct; as, a thick utterance.
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   7. Deep; profound; as, thick sleep. [R.] --Shak.
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   8. Dull; not quick; as, thick of fearing. --Shak.
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            His dimensions to any thick sight were invincible.
                                                  --Shak.
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   9. Intimate; very friendly; familiar. [Colloq.]
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            We have been thick ever since.        --T. Hughes.
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   Note: Thick is often used in the formation of compounds, most
         of which are self-explaining; as, thick-barred,
         thick-bodied, thick-coming, thick-cut, thick-flying,
         thick-growing, thick-leaved, thick-lipped,
         thick-necked, thick-planted, thick-ribbed,
         thick-shelled, thick-woven, and the like.
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   Thick register. (Phon.) See the Note under Register, n.,
      7.

   Thick stuff (Naut.), all plank that is more than four
      inches thick and less than twelve. --J. Knowles.
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   Syn: Dense; close; compact; solid; gross; coarse.
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