Titanic sinker (7)
I believe the answer is:
iceberg
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">titanic sinker</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 iceberg that I've seen before include "Frozen shipping hazard" , "Large mass of floating ice" , "Hazard of polar seas" , "shunned by sailors?" , "calf, perhaps" .)