Source : Webster's Revised Unabridged Dictionary (1913)

Gusto \Gus"to\, n. [It. or Sp., fr. L. gustus; akin to E.
   choose. Cf. 2d {GUST}, {GOUR}.]
   Nice or keen appreciation or enjoyment; relish; taste; fancy.
   --Dryden.

Source : WordNet®

gusto
     n : vigorous and enthusiastic enjoyment [syn: {relish}, {zest},
         {zestfulness}]