Not observed (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not observed</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unseen that I've seen before include "Invisable" , "Invisible or not observed" , "Not noticed" , "Translation exercise" , "Hidden from view" .)
(Other definitions for unnoticed that I've seen before include "Unperceived" , "Not registered" , "behind closed doors?" , "without attracting attention" , "Overlooked" .)