High poker pair (4)
I believe the answer is:
aces
'high poker pair' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aces that I've seen before include "Tennis serves the receiver can't reach" , "Two will make deuce" , "that are non-returnable" , "Top cards or people" , "Case of top cards" .)