Lady taking orders to and fro (3)
I believe the answer is:
nun
'lady' is the definition.
(I have seen 'Religious lady ' mean 'nun' so perhaps 'lady' could also mean 'nun')
'orders to and fro' is the wordplay.
I cannot quite see how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
The remaining letters 'un' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'taking' acts as a link.
Can you help me to learn more?
(Other definitions for nun that I've seen before include "religious person" , "Fancy pigeon variety" , "Devout woman" , "Woman with a habit" , "Member of religious order" .)