Horse that's not competitive for any course except the first (10)
I believe the answer is:
nonstarter
'horse' is the definition.
(nonstarter is a kind of horse)
'not competitive for any course except the first' is the wordplay.
I cannot really see how this works, but
'not' could be 'non' (I've seen this in other clues) and 'non' is found in the answer.
'course' could be 'starter' (course of a meal) and 'starter' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'that's' is the link.
Can you help me to learn more?
(Other definitions for nonstarter that I've seen before include "Something with no chance of success" , "Someone who is never going to succeed" , "unfeasible idea" , "Hopeless idea" , "Unviable thing" .)