[1] : The Collaborative International Dictionary of English v.0.48

knack \knack\ na^k, v. i. prob. of imitative origin; cf. g.
   knacken to break, dan. knage to crack, and e. knock.
   1. to crack; to make a sharp, abrupt noise to chink. obs. or
      prov. eng. --bp. hall.
      1913 webster

   2. to speak affectedly. prov. eng. --halliwell.
      1913 webster

[2] : The Collaborative International Dictionary of English v.0.48

knack \knack\, n.
   1. a petty contrivance; a toy; a plaything; a knickknack.
      1913 webster

            a knack, a toy, a trick, a baby's cap. --shak.
      1913 webster

   2. a readiness in performance; aptness at doing a specific
      task; skill; aptitude; facility; dexterity; -- often used
      with for; as, a knack for playing the guitar.
      1913 webster +pjc

            the fellow . . . has not the knack with his shears.
                                                  --b. jonson.
      1913 webster

            the dean was famous in his time,
            and had a kind of knack at rhyme.     --swift.
      1913 webster

   3. something performed, or to be done, requiring aptness and
      dexterity; a trick; a device. "the knacks of japers."
      --chaucer.
      1913 webster

            for how should equal colors do the knack  --pope.
      1913 webster

[3] : WordNet (r) 2.0

knack
     n : a special way of doing something; "he had a bent for it";
         "he had a special knack for getting into trouble"; "he
         couldn't get the hang of it" syn: bent, hang
see also:
bent hang 

[4] : Moby Thesaurus II by Grady Ward, 1.0

47 moby thesaurus words for "knack":
   ability, adroitness, aptitude, aptness, art, bauble, bent, bibelot,
   bric-a-brac, capacity, command, dexterity, expertise, expertism,
   expertness, facility, feel, flair, fribble, gaud, genius, gewgaw,
   gift, gimcrack, hang, head, intuition, kickshaw, knickknack,
   know-how, mastership, mastery, nose, proficiency, quickness,
   readiness, set, skill, swing, talent, touch, toy, trick, trinket,
   turn, way, whim-wham

Knack >> K Words
Knack, definition of term: Knack
knack_pag1.html