Want business to take on old soldier (5)
I believe the answer is:
covet
'want' is the definition.
(I've seen this before)
'business to take on old soldier' is the wordplay.
'business' becomes 'co'.
'to take on' is a charade indicator (letters next to each other).
'old soldier' becomes 'vet' (I've seen this before).
'co'+'vet'='COVET'
(Other definitions for covet that I've seen before include "Long to have (something belonging to another)" , "Envy" , "Hanker after" , "Jealously desire" , "Long enviously (to have something)" .)