Open just a crack (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
ajar
'open just a crack' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ajar that I've seen before include "Not to answer" , "Half-open" , "letting in a little light?" , "Not quite closed" , "(Door) to, not shut" .)