Unauthorised disclosure (4)
I believe the answer is:
leak
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unauthorised disclosure</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 leak that I've seen before include "Accidental hole that allows fluid to escape" , "Seep; disclose" , "Divulge" , "(Politically motivated) seepage?" , "Disclose (secrets)" .)