Honest woman twice left out (5)
I believe the answer is:
level
'honest' is the definition.
(level can mean fair or honest)
'woman twice left out' is the wordplay.
'woman' becomes 'eve' (Eve is an example).
'twice' indicates the doubling of some letters.
'left' becomes 'l' (common abbreviation).
'out' is an insertion indicator.
'l' doubled is 'll'.
'eve' put into 'll' is 'LEVEL'.
(Other definitions for level that I've seen before include "Horizontal line" , "Even - equal" , "Flatten" , "Palindromically smooth" , "Standard" .)