Reversals (1-5)
I believe the answer is:
u-turns
'reversals' is the definition.
(u-turn is a kind of reversal)
This is all the clue.
(Other definitions for u-turns that I've seen before include "Complete reversals, cars or decisions" , "Complete reversals, of direction or opinion" , "Complete reverses, cars or attitudes" , "Complete reversals of direction in car driving" , "Complete reversals, of cars or attitudes" .)