Apprentice loses head but he brings home the bacon (6)
I believe the answer is:
earner
'he brings home the bacon' is the definition.
(I've seen this in another clue)
'apprentice loses head' is the wordplay.
'apprentice' becomes 'learner' (synonyms).
'loses head' means to remove the first letter.
'learner' with its initial letter taken away is 'EARNER'.
'but' acts as a link.
(Other definitions for earner that I've seen before include "One in employment" , "Someone paid for work" , "One bringing in wage" , "Employee" , "one working for a living" .)