[1] : The Collaborative International Dictionary of English v.0.48

thorny \thorn"y\, a. compar. thornier; superl. thorniest.
   cf. as. thornorniht.
   1. full of thorns or spines; rough with thorns; spiny; as, a
      thorny wood; a thorny tree; a thorny crown.
      1913 webster

   2. like a thorn or thorns; hence, figuratively, troublesome;
      vexatious; harassing; perplexing. "the thorny point of
      bare distress." --shak.
      1913 webster

            the steep and thorny way to heaven.   --shak.
      1913 webster

   thorny rest-harrow bot., rest-harrow.

   thorny trefoil, a prickly plant of the genus fagonia
      fagonia cretica, etc..
      1913 webster
see also:
thornier thorniest thorny rest-harrow thorny trefoil fagonia fagonia cretica 

[2] : WordNet (r) 2.0

thorny
     adj 1: bristling with perplexities; "the thorny question of states'
            rights"
     2: having or covered with protective barbs or quills or spines
        or thorns or setae etc.; "a horse with a short bristly
        mane"; "bristly shrubs"; "burred fruits"; "setaceous
        whiskers" syn: barbed, barbellate, briary, briery,
         bristled, bristly, burred, burry, prickly, setose,
         setaceous, spiny
     also: thorniest, thornier
see also:
barbed barbellate briary briery bristled bristly 
burred burry prickly setose setaceous 
spiny thorniest thornier 

[3] : Moby Thesaurus II by Grady Ward, 1.0

72 moby thesaurus words for "thorny":
   herculean, abstruse, acanaceous, acanthoid, aciculate, aculeolate,
   arduous, barbed, barbellate, brambly, briery, bristly, brutal,
   complex, complicated, controversial, critical, delicate, demanding,
   difficile, difficult, exacting, formidable, hairy, hard,
   hard-earned, hard-fought, intricate, involved, jawbreaking,
   knotted, knotty, laborious, mean, muricate, nasty, nettlesome,
   no picnic, not easy, operose, painful, pricking, prickly, pricky,
   problematic, rigorous, rough, rugged, set with thorns, setaceous,
   setose, severe, spiculate, spiculose, spiked, spinous, spiny,
   steep, sticky, stinging, strenuous, tangled, thistly, ticklish,
   toilsome, tough, tricky, troublesome, uphill, vexatious, wicked,
   worrying

Thorny >> T Words
Thorny, definition of term: Thorny
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