Good hand (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">good hand</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 flush that I've seen before include "Cleanse by running water" , "Rouse game and put to flight" , "Level (with surface); put up (game bird)" , "Pull the chain - rush of emotion - good poker hand - having plenty of money" , "colour" .)