Slothful, lazy (4)
I believe the answer is:
idle
This clue is a double definition.
'slothful' is the first definition.
(similar in meaning)
'lazy' is the second definition.
(similar in meaning)
(Other definitions for idle that I've seen before include "'Lazy, not doing anything (4)'" , "Fruitless" , "Turn over" , "Still" , "Not in action or at work" .)