Controlling straps (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
reins
'controlling straps' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for reins that I've seen before include "Straps to control" , "Checks" , "Power to direct and control" , "Control for horses" , "Rider's straps" .)