You can have a 'jump' one, of course (5)
I believe the answer is:
start
'course' is the definition.
(thesaurus)
'you can have a jump one' is the wordplay.
I cannot really see how this works, but
'have' could be 'star' (starring is a kind of having) and 'star' is found in the answer.
A single letter 't' remains which might be clued in a way I don't understand.
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 start that I've seen before include "Move quickly < when surprised" , "Begin to recoil?" , "Jerk" , "Commence" , "Take the first step" .)