Varnish the woman will put on account (7)
I believe the answer is:
shellac
'varnish' is the definition.
(I know that shellac is a type of varnish)
'the woman will put on account' is the wordplay.
'the woman will' becomes 'she'll'.
'put on' says to put letters next to each other.
'account' becomes 'ac' (abbreviation for account).
'shell'+'ac'='SHELLAC'
(Other definitions for shellac that I've seen before include "Thin varnish used to finish wood" , "old record" , "Resin used in varnishes" , "Varnish derived from insect secretion" , "Defeat" .)