Was obliged to return after almost perfect seclusion (6)
I believe the answer is:
purdah
'seclusion' is the definition.
(purdah is a system of seclusion for women)
'was obliged to return after almost perfect' is the wordplay.
'was obliged' becomes 'had' (to have to do something is to be obliged to do it).
'to return' says the letters should be written backwards.
'after' says to put letters next to each other.
'almost perfect' becomes 'pur' (I can't explain this - if you can you should give a lot more credence to this answer).
'had' in reverse letter order is 'dah'.
'dah' put after 'pur' is 'PURDAH'.
Can you help me to learn more?
(Other definitions for purdah that I've seen before include "Hindu or Muslim seclusion of women" , "Hindu system of keeping women from sight of men" , "Eastern tradition of keeping women secluded" , "Period of seclusion" , "Screen - custom of keeping women in seclusion" .)