Slightly open (4)
I believe the answer is:
ajar
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">slightly open</span>' is the definition.<br/ ><span class="explanation-format__explanation">(as in a door left ajar)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ajar that I've seen before include "Raja (anag.)" , "Half open" , "It's nearly open" , "partly opened" , "not slammed shut" .)