Student failing to start easy cash job (6)
I believe the answer is:
earner
'easy cash job' is the definition.
'student failing to start' is the wordplay.
'student' becomes 'learner' (I've seen this before).
'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 "Something generating a good profit" , "Someone who receives wages in return for labour" , "Money-spinner" , "one working for a living" , "Breadwinner" .)