Work-shy superstar, they say (4)
I believe the answer is:
idle
'work-shy' is the definition.
(similar in meaning)
'superstar they say' is the wordplay.
'superstar' becomes 'idol' (idol can mean a celebrity).
'they say' indicates a 'sounds like' (homophone) clue.
'idol' is a homophone of 'IDLE'.
(Other definitions for idle that I've seen before include "Lazy - vain" , "Lied about being lazy or not working" , "not being engaged" , "not working in > lounge" , "Without work" .)