The Collaborative International Dictionary of English v.0.48:

Saucy \Sau"cy\, a. [Compar. Saucier; superl. Sauciest.]
   [From Sauce.]
   1. Showing impertinent boldness or pertness; transgressing
      the rules of decorum; treating superiors with contempt;
      impudent; insolent; as, a saucy fellow.
      [1913 Webster]

            Am I not protector, saucy priest?     --Shak.
      [1913 Webster]

   2. Expressive of, or characterized by, impudence;
      impertinent; as, a saucy eye; saucy looks.
      [1913 Webster]

            We then have done you bold and saucy wrongs. --Shak.
      [1913 Webster]

   Syn: Impudent; insolent; impertinent; rude.
        [1913 Webster]

WordNet (r) 3.0 (2006):

saucy
    adj 1: characterized by a lightly pert and exuberant quality; "a
           certain irreverent gaiety and ease of manner" [syn:
           impertinent, irreverent, pert, saucy]
    2: improperly forward or bold; "don't be fresh with me";
       "impertinent of a child to lecture a grownup"; "an impudent
       boy given to insulting strangers"; "Don't get wise with me!"
       [syn: fresh, impertinent, impudent, overbold,
       smart, saucy, sassy, wise]

Moby Thesaurus II by Grady Ward, 1.0:

55 Moby Thesaurus words for "saucy":
   arch, arrogant, audacious, bantam, biggety, bluff, bold, brash,
   brassy, brazen, bumptious, challenging, cheeky, chutzpadik, cocky,
   combative, contemptuous, contumelious, crusty, daring, defiant,
   defying, derisive, disdainful, disregardful, disrespectful, facy,
   flip, flippant, fresh, frivolous, gally, gratuitous,
   greatly daring, impertinent, impudent, insolent, intrusive,
   light-minded, malapert, meddlesome, nervy, obtrusive, pert,
   procacious, regardless of consequences, rude, sassy, smart,
   smart-alecky, smart-ass, uncalled-for, volatile, wise, wise-ass