[syn: baffling, elusive, knotty, problematic, problematical, tough]
The Collaborative International Dictionary of English v.0.48:
Elusive \E*lu"sive\, a.
   Tending to elude; using arts or deception to escape; adroitly
   escaping or evading; eluding the grasp; fallacious.
   [1913 Webster]
         Elusive of the bridal day, she gives
         Fond hopes to all, and all with hopes deceives. --Pope.
   -- E*lu"sive*ly, adv. -- E*lu"sive*ness, n.
   [1913 Webster]
WordNet (r) 3.0 (2006):
elusive
    adj 1: difficult to describe; "a haunting elusive odor"
    2: skillful at eluding capture; "a cabal of conspirators, each
       more elusive than the archterrorist"- David Kline
    3: difficult to detect or grasp by the mind or analyze; "his
       whole attitude had undergone a subtle change"; "a subtle
       difference"; "that elusive thing the soul" [syn: elusive,
       subtle]
    4: making great mental demands; hard to comprehend or solve or
       believe; "a baffling problem"; "I faced the knotty problem of
       what to have for breakfast"; "a problematic situation at
       home" [syn: baffling, elusive, knotty, problematic,
       problematical, tough]
Moby Thesaurus II by Grady Ward, 1.0:
21 Moby Thesaurus words for "elusive":
   baffling, cagey, elusory, evanescent, evasive, fleeting, fugitive,
   impalpable, imponderable, incomprehensible, indefinable,
   insubstantial, intangible, malingering, mysterious, phantom,
   shifty, shirking, slippery, transitory, tricky