Prefer to tell on that woman (6)
I believe the answer is:
rather
'prefer to' is the definition.
(I've seen this in another clue)
'tell on that woman' is the wordplay.
'tell' becomes 'rat' (I've seen this in another clue).
'on' says to put letters next to each other.
'that woman' becomes 'her' (her refers to a woman).
'rat'+'her'='RATHER'
(Other definitions for rather that I've seen before include "somewhat > sooner? > Quite" , "Preferably, instead" , "On the contrary; more precisely" , "More willingly, by preference" , "On the contrary or to some extent" .)