The Collaborative International Dictionary of English v.0.48:

Thickset \Thick"set`\, n.
   1. A close or thick hedge.
      [1913 Webster]

   2. A stout, twilled cotton cloth; a fustian corduroy, or
      velveteen. --McElrath.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Thickset \Thick"set`\, a.
   1. Close planted; as, a thickset wood; a thickset hedge.
      --Dryden.
      [1913 Webster]

   2. Having a short, thick body; stout.
      [1913 Webster]

WordNet (r) 3.0 (2006):

thickset
    adj 1: having a short and solid form or stature; "a wrestler of
           compact build"; "he was tall and heavyset"; "stocky
           legs"; "a thickset young man" [syn: compact,
           heavyset, stocky, thick, thickset]
    2: planted or growing close together; "thickset trees"

Moby Thesaurus II by Grady Ward, 1.0:

113 Moby Thesaurus words for "thickset":
   able-bodied, adipose, athletic, beefy, big-bellied, bloated,
   blocky, blowzy, bosomy, brawny, broad-bodied, broad-shouldered,
   bulky, bullnecked, burly, buxom, chubby, chunky, close, close-knit,
   close-textured, close-woven, coarse, compact, compacted,
   compressed, concentrated, concrete, condensed, congested,
   consolidated, corpulent, crammed, crammed full, crass, crowded,
   dense, distended, dumpy, fat, fattish, firm, fleshy, full,
   full-bodied, gluey, gross, hard, heavy, heavyset, hefty, hippy,
   impenetrable, impermeable, imposing, jam-packed, jammed, lusty,
   massive, meaty, muscle-bound, muscular, nonporous, obese,
   overweight, packed, paunchy, plump, podgy, portly, potbellied,
   pudgy, puffy, pug, pugged, pursy, retrousse, roly-poly, rotund,
   serried, sinewy, snub-nosed, solid, square, squat, squattish,
   squatty, stalwart, stocky, stout, strapping, stubbed, stubby,
   stumpy, substantial, swollen, thewy, thick, thick-bodied,
   thick-growing, three-dimensional, top-heavy, tubby, turned-up,
   viscid, viscose, viscous, well-built, well-fed, well-knit,
   well-set, well-set-up, wiry