briskness       
noun [ U ] uk/ˈbrɪsk.nəs/ us/ˈbrɪsk.nəs/
 轻快,生气勃勃
the quality of being quick and energetic
  She climbed the stairs with her usual briskness. 她像往常一样轻快地爬上楼梯。 
 They headed to the car with a youthful briskness. 他们朝汽车走去,青春飞扬,神采奕奕。 
 See: brisk
 - More examples
 - The briskness of the brushstrokes suggests quick, unplotted movement in the painting.
 - Business was conducted with briskness and professionalism.
 - Their conversational tone alternated jocularity and briskness.