Student failing to start job? (6)
I believe the answer is:
earner
'job?' is the definition.
(I have seen 'Good job' mean 'earner' so perhaps 'job' could also mean 'earner')
'student failing to start' is the wordplay.
'student' becomes 'learner' (someone who is learning).
'failing to start' means to remove the first letter.
'learner' with its initial letter taken away is 'EARNER'.
(Other definitions for earner that I've seen before include "One who gets money for work" , "Employee" , "Cash job" , "One in employment" , "One bringing in wage" .)