Instead changed the first to “repugnance” (8)
I believe the answer is:
distaste
'repugnance' is the definition.
(I've seen this before)
'instead changed the first' is the wordplay.
I cannot quite see how this works, but
'first' could be 'ist' and 'ist' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for distaste that I've seen before include "Loathing" , "Mild horror" , "Mild dislike, aversion" , "Feeling of dislike - unsavoury?" , "Adverse reaction" .)