Film horse-trader's plug for docile pony (4,5)
I believe the answer is:
easy rider
'film' is the definition.
(I've seen this before)
'horse-trader's plug for docile pony' is the wordplay.
I cannot quite understand how this works, but
'horse' could be 'ride' and 'ride' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for easy rider that I've seen before include "1969 road movie" , "counter-culture movie" , "Picture" , "Film about motor cyclists' travels" , "Peter Fonda film" .)