Spiritlessness (6)
I believe the answer is:
apathy
'spiritlessness' is the definition.
(I know that spiritlessness can be written as apathy)
This is all the clue.
(Other definitions for apathy that I've seen before include "Lack of excitement" , "Lack of interest in things in general" , "Lack of emotion and interest" , "Indifference, emotionlessness" , "Complete lack of interest, indifference" .)