Experts showing no duplication in approach? (4)
I believe the answer is:
aces
'experts' is the definition.
(ace is a kind of expert)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for aces that I've seen before include "Two will make deuce" , "Top cards or people" , "Experts (in their field)" , "winning shots" , "never come back" .)