The Collaborative International Dictionary of English v.0.48:

Smack \Smack\, v. i. [imp. & p. p. Smacked; p. pr. & vb. n.
   Smacking.] [OE. smaken to taste, have a taste, -- from the
   noun; cf. AS. smecan taste; akin to D. smaken, G. schmecken,
   OHG. smechen to taste, smach?n to have a taste (and, derived
   from the same source, G. schmatzen to smack the lips, to kiss
   with a sharp noise, MHG. smatzen, smackzeen), Icel. smakka to
   taste, Sw. smaka, Dan. smage. See 2d Smack, n.]
   1. To have a smack; to be tinctured with any particular
      taste.
      [1913 Webster]

   2. To have or exhibit and indication or suggestion of the
      presence of any character or quality; to have a taste, or
      flavor; -- used with of; as, a remark smacking of
      contempt.
      [1913 Webster + PJC]

            All sects, all ages, smack of this vice. --Shak.
      [1913 Webster]

   3. To kiss with a close compression of the lips, so as to
      make a sound when they separate; to kiss with a sharp
      noise; to buss.
      [1913 Webster]

   4. To make a noise by the separation of the lips after
      tasting anything.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Smacking \Smack"ing\, n.
   A sharp, quick noise; a smack.
   [1913 Webster]

         Like the faint smacking of an after kiss. --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Smacking \Smack"ing\ (sm[a^]k"[i^]ng), a.
   Making a sharp, brisk sound; hence, brisk; as, a smacking
   breeze.
   [1913 Webster]

WordNet (r) 3.0 (2006):

smacking
    n 1: the act of smacking something; a blow delivered with an
         open hand [syn: smack, smacking, slap]

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "smacking":
   active, activist, activistic, acute, aggressive, alive, animated,
   bouncing, bouncy, breezy, brisk, bubbly, chipper, dynamic,
   ebullient, effervescent, energetic, enterprising, enthusiastic,
   forceful, forcible, frisky, full of go, full of life, full of pep,
   go-go, hearty, impetuous, incisive, intense, keen, kinetic, live,
   lively, living, lusty, mercurial, mettlesome, militant, peppy,
   perky, pert, quicksilver, robust, snappy, spanking, spirited,
   sprightly, spry, strenuous, strong, take-charge, take-over,
   trenchant, vibrant, vigorous, vivacious, vivid, zestful, zesty,
   zingy, zippy