Confess, admit (3,2)
I believe the answer is:
own up
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">confess</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">admit</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know this)</span><br/ ><br/ ></span>
(Other definitions for own up that I've seen before include "Accept responsibility" , "be honest" , "Confess, admit guilt (3.2)" , "Come clean (about wrongdoing)" , "Confess, acknowledge fault" .)