Work away, almost leisurely, to get a lot of money (4)
I believe the answer is:
slog
'work away' is the definition.
(thesaurus)
'almost leisurely to get a lot of money' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'leisurely' becomes 'slow' (I've seen this before).
'to get' means one lot of letters go next to another.
'a lot of money' becomes 'g'.
'slow' with its last letter removed is 'slo'.
'slo'+'g'='SLOG'
(Other definitions for slog that I've seen before include "Hit out without style" , "Very tiring work" , "Work (or walk) involving great effort" , "Wild cricket hit" , "Work doggedly" .)