Quintet for river dweller (5)
I believe the answer is:
trout
'dweller' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'quintet for river' is the wordplay.
I cannot quite see how this works, but
'river' could be 'r' and 'r' is located in the answer.
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is located in the leftover letters.
The remaining letters 'ut' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for trout that I've seen before include "Tasty fish, brown or rainbow" , "Schubert Quintet?" , "Schubert work; fish" , "Edible fish" , "Swimmer" .)