Tattoo (3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tattoo</span>' is the definition.<br/ ><span class="explanation-format__explanation">(ink can informally mean a tattoo)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ink that I've seen before include "Writing fluid" , "Pen's contents" , "Cuttlefish defence" , "Liquid used to write" , "Cuttlefish's secretion" .)