Source : Webster's Revised Unabridged Dictionary (1913)

Natty \Nat"ty\, a. [Cf. {Neat} clean.]
   Neat; tidy; spruce. [Colloq.] -- {Nat"ti*ly}, adv. --
   {Nat"ti*ness}, n.

Source : WordNet®

nattiness
     n : stylishness as evidenced by a smart appearance [syn: {jauntiness},
          {dapperness}, {rakishness}]