Titled Turk this month in opposition (7)
I believe the answer is:
against
'in opposition' is the definition.
(I've seen this in another clue)
'titled turk this month' is the wordplay.
'titled turk' becomes 'aga' (I've seen this in another clue).
'this month' becomes 'inst' (letter-writing abbreviation for this month).
'aga'+'inst'='AGAINST'
(Other definitions for against that I've seen before include "Not supporting" , "In disagreement with" , "Opposed" , "Opposite to" , "Placed in direct contact with" .)