Clear strategy contains Iran initially (5)
I believe the answer is:
plain
'clear' is the definition.
(I've seen this before)
'strategy contains iran initially' is the wordplay.
'strategy' becomes 'plan' (I've seen this before).
'contains' means one lot of letters goes inside another.
'initially' indicates taking the first letters.
The first letter of 'iran' is 'i'.
'plan' enclosing 'i' is 'PLAIN'.
(Other definitions for plain that I've seen before include "Geographical feature" , "lament" , "Flat land; unmarked" , "Not complicated" , "Simple, ordinary" .)