The Collaborative International Dictionary of English v.0.48:

Suave \Suave\, a. [L. suavis sweet, pleasant: cf. F. suave. See
   Sweet, and cf. Suasion.]
   Sweet; pleasant; delightful; gracious or agreeable in manner;
   bland. -- Suave"ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

suave
    adj 1: having a sophisticated charm; "a debonair gentleman"
           [syn: debonair, debonaire, debonnaire, suave]
    2: smoothly agreeable and courteous with a degree of
       sophistication; "he was too politic to quarrel with so
       important a personage"; "the manager pacified the customer
       with a smooth apology for the error" [syn: politic,
       smooth, suave, bland]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "suave":
   affable, agreeable, bland, buttery, charming, civilized, cordial,
   cosmopolitan, courteous, courtly, cultivated, cultured, debonair,
   diplomatic, disarming, distingue, downy, even, fair-spoken,
   fine-spoken, flat, fulsome, genial, glabrate, glabrescent,
   glabrous, glib, gracious, honey-mouthed, honey-tongued,
   ingratiating, leiotrichous, level, nonchalant, oily, oily-tongued,
   plane, polished, polite, politic, refined, regular, slick, smooth,
   smooth-shaven, smooth-spoken, smooth-textured, smooth-tongued,
   smug, soapy, sociable, soft, soft-spoken, sophisticated,
   suave-spoken, unbroken, unctuous, uniform, unrough, unroughened,
   unruffled, urbane, well-bred, worldly