Forbidden woman entering base (6)
I believe the answer is:
banned
'forbidden' is the definition.
(banning is a kind of forbidding)
'woman entering base' is the wordplay.
'woman' becomes 'ann' (woman's name).
'entering' is an insertion indicator.
'base' becomes 'bed' (both can mean the bottom of something).
'ann' going inside 'bed' is 'BANNED'.
(Other definitions for banned that I've seen before include "Prohibited officially" , "Prohibited by censor" , "Outlawed" , "Barred" , "Legally prohibited" .)