Paramour soon gets a sailor put up (9)
I believe the answer is:
inamorata
'paramour' is the definition.
(thesaurus)
'soon gets a sailor put up' is the wordplay.
'soon' becomes 'in a mo' (in a mo).
'gets' means one lot of letters go next to another.
'sailor' becomes 'tar' (slang term for a sailor).
'put up' shows that the letters should be reversed in order.
'a'+'tar'='atar'
'atar' written backwards gives 'rata'.
'inamo'+'rata'='INAMORATA'
(Other definitions for inamorata that I've seen before include "Beloved of one another" , "loved one" , "A woman loved" , "Female lover" , "6 across [BOSOM] friend" .)