Not many are in safe work (3)
I believe the answer is:
few
'not many' is the definition.
('few' is the opposite to 'many')
'in safe work' is the wordplay.
'in' indicates a hidden word.
'FEW' is hidden in the letters of 'safe work'.
'are' is the link.
(Other definitions for few that I've seen before include "Not many, just a handful" , "Relatively small number" , "'''Many are called but ... are chosen'' (Bible) (3)'" , "Considerable number, ironically" , "Hardly anyone" .)