Understands; watches (4)
I believe the answer is:
sees
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">understands</span>' is the first definition.<br/ ><span class="explanation-format__explanation">('see' can be a synonym of 'understand')</span><br/ ><br/ >'<span class="explanation-format__original">watches</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know this)</span><br/ ><br/ ></span>
(Other definitions for sees that I've seen before include "Bishoprics" , "Notices" , "Looks (both ways!)" , "Clocks" , "Observes or perceives" .)