Listlessness, lethargy (9)
I believe the answer is:
lassitude
This clue is a double definition.
'listlessness' is the first definition.
(I know that listlessness can be written as lassitude)
'lethargy' is the second definition.
(I know that lethargy can be written as lassitude)
(Other definitions for lassitude that I've seen before include "slackness" , "Lack of energy and enthusiasm" , "Listlessness, fatigue" , "Sluggishness" , "30 [LETHARGY]" .)