Just working before end of financial year (4)
I believe the answer is:
only
'just' is the definition.
(I know that just can be written as only)
'working before end of financial year' is the wordplay.
'working' becomes 'on' (e.g. a machine is working or on).
'before' is a charade indicator (letters next to each other).
'end of' says to take the final letters.
'year' becomes 'y'.
The last letter of 'financial' is 'l'.
'on'+'l'+'y'='ONLY'
(Other definitions for only that I've seen before include "Exclusive - individual" , "Alone; solitary" , "Except that; single" , "Solely; except that" , "Mere" .)