High or low cards (4)
I believe the answer is:
aces
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">high or low cards</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for aces that I've seen before include "Honours" , "never come back" , "Two will make deuce" , "They're high and low on cards" , "Winning serves" .)