Make a splash with her in the river (5)
I believe the answer is:
rhine
'river' is the definition.
(Rhine River is an example)
'make a splash with her in' is the wordplay.
'her in' anagrams to 'RHINE'.
But, I am unsure how the anagram is indicated.
'the' is the link.
Can you help me to learn more?
(Other definitions for rhine that I've seen before include "Major European river" , "fed by 8 [RHUR]" , "Great European river with Lorelei Rock" , "Great river that flows through Germany" , "River of Cologne" .)