Obstreperous Russian initially rejected communist's directive (5)
I believe the answer is:
order
'directive' is the definition.
(I've seen this before)
'obstreperous russian initially rejected communist's' is the wordplay.
'initially' indicates taking the first letters.
'rejected' shows that the letters should be reversed in order.
'communist' becomes 'red' (red is a kind of communist).
The initial letters of 'obstreperous russian' is 'or'.
'red' backwards is 'der'.
'or'+'der'='ORDER'
(Other definitions for order that I've seen before include "Decree" , "kind > direction" , "Enjoin in harmony" , "Call" , "Select from menu" .)