Turkish commander about to finish items for discussion (6)
I believe the answer is:
agenda
'items for discussion' is the definition.
(I've seen this before)
'turkish commander about to finish' is the wordplay.
'turkish commander' becomes 'aga' (I've seen this before).
'about' means one lot of letters goes inside another.
'to finish' becomes 'end' ('end' can be a synonym of 'finish').
'aga' placed around 'end' is 'AGENDA'.
(Other definitions for agenda that I've seen before include "Plan for meeting" , "List of items to be done" , "Table of business" , "plan of things to be done" , "Something perhaps hidden" .)