Inadequate society quits idling (7)
I believe the answer is:
lacking
'inadequate' is the definition.
(similar in meaning)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for lacking that I've seen before include "Short" , "Being without, wanting" , "Deficient or inadequate" , "Absent, deficient" , "Missing" .)