North Star (7)
I believe the answer is:
polaris
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">north star</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for polaris that I've seen before include "Star useful for navigation" , "one belonging in the heavens" , "weapon sailors unleash" , "North Star - missile" , "Star near the N pole of the heavens" .)