Watchful, alert (4-4)
I believe the answer is:
open-eyed
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">watchful</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">alert</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for open-eyed that I've seen before include "Astonished; fully aware" , "Surprised - aware" , "Astonished - watchful" , "Forming an encrusted mass" .)