Swimmer heading for home going off course (7)
I believe the answer is:
herring
'swimmer' is the definition.
(herring is a type of fish)
'heading for home going off course' is the wordplay.
I cannot really see how this works, but
'home' could be 'in' ('he's home' can mean 'he's in') and 'in' is found in the answer.
'course' could be 'e' and 'e' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for herring that I've seen before include "one could be soused" , "Sea fish" , "Fatty fish" , "Important food fish" , "Saltwater fish" .)