Fold or wrinkle (6)
I believe the answer is:
crease
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">fold</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(creasing is a kind of folding)</span><br/ ><br/ >'<span class="explanation-format__original">wrinkle</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for crease that I've seen before include "Cricket line; wrinkle" , "Dagger rarely" , "Line on a cricket pitch" , "batsman reaching it" , "feature of smart trousers" .)