perkiness       
noun [ U ] uk/ˈpɜː.ki.nəs/ us/ˈpɝː.ki.nəs/
 快乐,活跃,生机勃勃
the quality or state of being happy and full of energy
  Beneath her surface perkiness she is awfully dull. 在表面的活泼之下,她其实是非常沉闷的。 
 Her perkiness was both endearing and a little annoying. 她的活泼既让人喜爱,又有点让人生厌。 
 See: perky
 - More examples
 - She is the reigning world champion, a bundle of perkiness and power.
 - He felt so well-rested that friends remarked on his unexpected morning perkiness.
 - He was a model of perkiness, despite the fact that the show was going out live at 4.30 a.m. local time.