noun

the quality of being full of energy, excitement, and cheerfulness; ebullience.

a sense of youthful exuberance

ebullience,buoyancy,cheerfulness,sunniness,breeziness,jauntiness,light-heartedness,high spirits,exhilaration,excitement,elation,exultation,euphoria,joy,joyfulness,cheeriness,gaiety,jubilation,sparkle,effervescence,vivacity,enthusiasm,irrepressibility,energy,animation,life,liveliness,vigour,zest,bubble,bounce,pep,zing,chirpiness,peartness,gladsomeness,blitheness,blithesomeness,good cheer,luxuriance,lushness,richness,abundance,superabundance,profusion,proliferation,copiousness,riotousness,denseness,thickness,jungle,plentifulness,prolificness,rankness,rampancy