Obsession of jockey perhaps aboard last horse at The Curragh? Keep an eye on him! (3-5,4)
I believe the answer is:
one-track mind
'obsession' is the definition.
(I've seen this before)
'jockey perhaps aboard last horse at the curragh? keep an eye on him' is the wordplay.
I cannot quite understand how this works, but
'aboard' could be 'in' (I've seen this in other clues) and 'in' is found within the answer.
'last' could be 't' (I've seen this in other clues) and 't' is located in the answer.
'at' could be 'on' (location) and 'on' is found within the answer.
'an' could be 'a' and 'a' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for one-track mind that I've seen before include "Very basic obsession?" , "Brain preoccupied with a single subject" , "Obsessive attitude to a subject" , "A very limited thinker?" , "Obsession with a single objective" .)