Five found in river by dock making progress (7)
I believe the answer is:
develop
'progress' is the definition.
(thesaurus)
'five found in river by dock' is the wordplay.
'five' becomes 'v' (roman numeral).
'found in' indicates putting letters inside.
'river' becomes 'dee' (River Dee**).
'by' says to put letters next to each other.
'dock' becomes 'lop'.
'v' inserted inside 'dee' is 'deve'.
'deve'+'lop'='DEVELOP'
'making' acts as a link.
(Other definitions for develop that I've seen before include "issue" , "Work out in more detail" , "Become more advanced" , "'Grow, evolve (7)'" , "Result" .)