Butter up female, second of two (7)
I believe the answer is:
flatter
'butter up' is the definition.
(I've seen this in another clue)
'female second of two' is the wordplay.
'female' becomes 'f' (abbreviation).
'second of two' becomes 'latter' (I've seen this in another clue).
'f'+'latter'='FLATTER'
(Other definitions for flatter that I've seen before include "when all smoothed out?" , "more lifeless" , "Praise insincerely" , "suit, looking good" , "flannel" .)