Card game for one player (9)
I believe the answer is:
solitaire
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">card game for one player</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for solitaire that I've seen before include "Patience game" , "songbird" , "Single stone in jewellery" , "Patience of Americans" , "One-gem ring; one-player game" .)