Woman in Holy Writ displaying sagacity? Not so (9)
I believe the answer is:
otherwise
'not so' is the definition.
(I've seen this before)
'woman in holy writ displaying sagacity?' is the wordplay.
'woman' becomes 'her' (her refers to a woman).
'in' means one lot of letters goes inside another.
'holy writ' becomes 'OT' (Old Testament).
'displaying sagacity?' becomes 'wise' (I can't explain this - if you can you should believe this answer much more).
'ot'+'wise'='otwise'
'her' inserted within 'otwise' is 'OTHERWISE'.
Can you help me to learn more?
(Other definitions for otherwise that I've seen before include "White rose (anag.)" , "in different circumstances" , "Apart from that" , "Differently - or else!" , "Under different conditions" .)