Cast reel (5)
I believe the answer is:
fling
This clue could be a double definition.
'cast' is the first definition.
(both can mean to throw)
'reel' is the second definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see an association between them that I don't see?
Can you help me to learn more?
(Other definitions for fling that I've seen before include "Brief relationship" , "Vigorous Scottish dance" , "Brief affair; throw" , "Throw violently" , "Brief affair - chuck" .)