Champion conquers peak before she intermittently feels weakness (8,4)
I believe the answer is:
achilles heel
'weakness' is the definition.
(Achilles' heel is an example)
'champion conquers peak before she intermittently feels' is the wordplay.
I cannot quite see how this works, but
'champion' could be 'ch' (I've seen this in other clues) and 'ch' is present in the answer.
an anagram of 'she' is 'esh' which is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for achilles heel that I've seen before include "Small but crucial weakness" , "Weak spot for attack" , "A chink in the armour" , "Person's weak spot" , "Only vulnerable point" .)