Person who hurls racket in the river (7)
I believe the answer is:
thrower
'person who hurls' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'racket in the river' is the wordplay.
'racket' becomes 'row' (both can mean a noisy disturbance).
'in' means one lot of letters goes inside another.
'river' becomes 'r' (abbreviation for river).
'row' inserted inside 'the' is 'throwe'.
'throwe'+'r'='THROWER'
Can you help me to learn more?
(Other definitions for thrower that I've seen before include "tosser" , "shyer" , "One who intentionally loses" , "who offends the umpire?" , "participant in discus event?" .)