Vein in the neck (7)
I believe the answer is:
jugular
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vein in the neck</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for jugular that I've seen before include "Large 24 in neck" , "Large vein in the neck" , "Vein (go for it!)" , "Type of 25" .)