Rower using old cash machine in bar (7)
I believe the answer is:
boatman
'rower' is the definition.
(thesaurus)
'old cash machine in bar' is the wordplay.
'old' becomes 'o' (abbreviation).
'cash machine' becomes 'atm' (synonyms).
'in' means one lot of letters goes inside another.
'bar' becomes 'ban' (bar can mean to ban or prohibit).
'o'+'atm'='oatm'
'oatm' going inside 'ban' is 'BOATMAN'.
'using' acts as a link.
(Other definitions for boatman that I've seen before include "He may have a smack" , "George - or Harris, maybe" , "One in charge of a small vessel" , "Sailor" , "Water transport provider" .)