Naval NCO (5,7)
I believe the answer is:
petty officer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">naval nco</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 petty officer that I've seen before include "Naval NCO" , "rank" , "Sailor" , "Navy NCO" .)