According to Spooner, hardworking person is idle (6)
I believe the answer is:
loiter
'idle' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for loiter that I've seen before include "Stand around aimlessly" , "Stand around idly" , "Skulk" , "Hang around, lurk" , "Linger aimlessly" .)