Recalled Brezhnev ordering them to reveal what impelled them (5)
I believe the answer is:
drove
'impelled them' is the definition.
I can't tell whether this defines the answer.
'recalled brezhnev ordering them to reveal' is the wordplay.
'recalled' says the letters should be written in reverse (to recall can mean to bring something back).
'to reveal' indicates a hidden word.
'evord' is hidden within 'brezhnev ordering them'.
'evord' back-to-front is 'DROVE'.
'what' is the link.
Can you help me to learn more?
(Other definitions for drove that I've seen before include "Moving company" , "Horde" , "Group of animals" , "Flock of animals being driven" , "Motored; moving flock" .)