Listless; indolent (13)
I believe the answer is:
lackadaisical
This clue is a double definition.
'listless' is the first definition.
(I've seen this before)
'indolent' is the second definition.
(I've seen this before)
(Other definitions for lackadaisical that I've seen before include "Listless" , "Spiritless" , "Lethargic" , "Wanting enthusiasm" , "Apathetic" .)