Crossword Genius

Countermand order I've set in motion (8)

Ross

I believe the answer is:

'countermand' is the definition.
(I've seen this before)

'order i've set in motion' is the wordplay.
'set in motion' indicates anagramming the letters (letters made to move around).
'order'+'ive'='orderive'
'orderive' is an anagram of 'OVERRIDE'.

(Other definitions for override that I've seen before include "Outweigh; cancel", "Disregard", "Use one's authority to reject or cancel a decision", "Take manual control", "Set aside by superior authority".)

I've seen this clue in The Telegraph.