Deprive of sustenance (6)
I believe the answer is:
starve
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">deprive of sustenance</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for starve that I've seen before include "Suffer from lack of food" , "Suffer extreme hunger" , "Deprive of sustenance" , "Without wishing, fast" , "Suffer from want of food" .)