Hinder, frustrate (6)
I believe the answer is:
stymie
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">hinder</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that hinder can be written as stymie)</span><br/ ><br/ >'<span class="explanation-format__original">frustrate</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for stymie that I've seen before include "Obstruction (originally at golf)" , "Block; hinder" , "balk" , "Situation from which it is almost impossible to proceed" , "Impede, say golf stroke" .)