Tours to be enjoyed on this river (5)
I believe the answer is:
loire
'this river' is the definition.
(Loire River is an example)
'tours to be enjoyed on' is the wordplay.
I cannot really see how this works, but
'on' could be 're' (regarding) and 're' is located in the answer.
The remaining letters 'loi' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for loire that I've seen before include "River of central France" , "River flowing through Tours and Nantes" , "France's longest river" , "Longest French river" , "French runner" .)