The Collaborative International Dictionary of English v.0.48:

Libidinous \Li*bid"i*nous\ (-n[u^]s), a. [L. libidinosus, fr.
   libido, libidinis, pleasure, desire, lust, fr. libet, lubet,
   it pleases: cf. F. libidineux. See Lief.]
   Having lustful desires; characterized by lewdness; sensual;
   lascivious. -- Li*bid"i*nous*ly, adv. --
   Li*bid"i*nous*ness, n.
   [1913 Webster]

   Syn: Lewd; lustful; lascivious; unchaste; impure; sensual;
        licentious; lecherous; salacious.
        [1913 Webster]

WordNet (r) 3.0 (2006):

libidinous
    adj 1: driven by lust; preoccupied with or exhibiting lustful
           desires; "libidinous orgies" [syn: lascivious, lewd,
           libidinous, lustful]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "libidinous":
   animal, aphrodisiomaniacal, appetitive, bawdy, carnal,
   clitoromaniacal, coarse, concupiscent, desiderative, desireful,
   desiring, desirous, dirty, eager, ejaculatory, erotic,
   eroticomaniacal, erotomaniacal, fast, fleshly, goatish, gross,
   gynecomaniacal, hoping, hormic, horny, hot, hot-blooded,
   hysteromaniacal, incontinent, itching, ithyphallic, lascivious,
   lecherous, lewd, libertine, libidinal, lickerish, lubricious,
   lustful, needing, nymphomaniacal, obscene, optative, orgasmic,
   orgastic, passionate, priapic, prurient, randy, salacious, satyric,
   sensual, sex-starved, sexual, sexy, steamy, tempted, unsatisfied,
   wanting, wishing