Bop on the head
I believe the answer is:
conk
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bop on the head</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for conk that I've seen before include "Nose (colloq.)" , "Hooter" , "Slangy nose or head" , "(Slang) nose - head" , "Nose; break down" .)