Magritte and wife start again (5)
I believe the answer is:
renew
'start again' is the definition.
(to renew something is to start it again)
'magritte and wife' is the wordplay.
'magritte' becomes 'rene' (Rene Magritte).
'and' says to put letters next to each other.
'wife' becomes 'w'.
'rene'+'w'='RENEW'
(Other definitions for renew that I've seen before include "Restore to original state" , "Extend loan period" , "Take up again" , "Transform born-again" , "Establish again" .)