The Collaborative International Dictionary of English v.0.48:

genuine \gen"u*ine\, a. [L. genuinus, fr. genere, gignere, to
   beget, in pass., to be born: cf. F. g['e]nuine. See
   Gender.]
   Belonging to, or proceeding from, the original stock; native;
   hence, not counterfeit, spurious, false, or adulterated;
   authentic; real; natural; true; pure; as, a genuine text; a
   genuine production; genuine materials. "True, genuine night."
   --Dryden.

   Syn: Authentic; real; true; pure; unalloyed; unadulterated.
        See Authentic. -- Gen"u*ine*ly, adv. --
        Gen"u*ine*ness, n.
        [1913 Webster]

              The evidence, both internal and external, against
              the genuineness of these letters, is overwhelming.
                                                  --Macaulay.
        [1913 Webster]

WordNet (r) 3.0 (2006):

genuine
    adj 1: not fake or counterfeit; "a genuine Picasso"; "genuine
           leather" [syn: genuine, echt] [ant: counterfeit,
           imitative]
    2: not pretended; sincerely felt or expressed; "genuine
       emotion"; "her interest in people was unfeigned"; "true
       grief" [syn: genuine, true(a), unfeigned]
    3: being or reflecting the essential or genuine character of
       something; "her actual motive"; "a literal solitude like a
       desert"- G.K.Chesterton; "a genuine dilemma" [syn: actual,
       genuine, literal, real]

Moby Thesaurus II by Grady Ward, 1.0:

139 Moby Thesaurus words for "genuine":
   aboveboard, absolute, actual, arcadian, artless, authentic, bluff,
   blunt, bona fide, broad, brusque, bucolic, candid, card-carrying,
   de facto, dinkum, direct, downright, earnest, explicit, factual,
   fair and square, following the letter, for real, forthright,
   foursquare, frank, frankhearted, free, free-speaking, free-spoken,
   free-tongued, good, good-faith, heart-to-heart, historical,
   homespun, honest, honest-to-God, inartificial, ingenuous, lawful,
   legitimate, lifelike, literal, native, natural, naturalistic,
   naturelike, on the level, on the square, on the up-and-up, open,
   open and aboveboard, openhearted, original, outspoken, pastoral,
   plain, plain-spoken, positive, proper, pukka, pure, real,
   realistic, rightful, round, rural, simon-pure, simple, sincere,
   single-hearted, square, square-dealing, square-shooting, sterling,
   straight, straight-out, straight-shooting, straightforward,
   substantial, sure-enough, transparent, true, true to life,
   true to nature, true to reality, unadorned, unadulterated,
   unaffected, unartificial, unassumed, unassuming, unchecked,
   uncolored, unconcocted, unconstrained, uncopied, uncounterfeited,
   undeniable, undesigning, undisguised, undisguising, undissembling,
   undissimulating, undistorted, unembellished, unequivocal,
   unexaggerated, unfabricated, unfanciful, unfeigned, unfeigning,
   unfictitious, unflattering, unguarded, unimagined, unimitated,
   uninvented, unpretended, unpretending, unpretentious, unqualified,
   unreserved, unrestrained, unromantic, unsimulated, unspecious,
   unspoiled, unsynthetic, unvarnished, up-and-up, verbal, verbatim,
   veridical, verisimilar, veritable, word-for-word