Case confusing experts (4)
I believe the answer is:
aces
'experts' is the definition.
(ace is a kind of expert)
'case confusing' is the wordplay.
'confusing' indicates an anagram.
'case' anagrammed gives 'ACES'.
(Other definitions for aces that I've seen before include "Unreturnable services" , "wartime pilots?" , "Two will make deuce" , "Expert fliers" , "excellent service" .)