Just — almost not (8)
I believe the answer is:
scarcely
I believe this clue is a double definition.
'just' is the first definition.
(I know that just can be written as scarcely)
'almost not' is the second definition.
(I've seen this before)
(Other definitions for scarcely that I've seen before include "Barely, hardly" , "Only just or hardly even" , "Almost not" , "Not quite" , "Surely not" .)